Occupiers' LiabilityThis is really a statutory tort, grounded in the Occupiers' Liability Act.
The leading SCC case Waldick v Johnson (SCC, 1991) is linked here but doesn't lend itself well to extracts.
. Campbell v. Bruce (County)
In Campbell v. Bruce (County) (Ont CA, 2016) the Court of Appeal commented as follows on the nature of the duty of care imposed by s.3 of the Occupier's Liability Act:
 ....... The leading case dealing with duty of care under the OLA is Waldick v. Malcolm, 1991 CanLII 71 (SCC),  2 S.C.R. 456. In that case, Iacobucci J. articulated the purpose of the OLA, at 477:. MacKay v. Starbucks Corporation
The goals of the Act are to promote, and indeed, require where circumstances warrant, positive action on the part of occupiers to make their premises reasonably safe. Iacobucci J. also discussed the contents of the duty of care under the OLA, at 472:
[T]he statutory duty on occupiers is framed quite generally, as indeed it must be. That duty is to take reasonable care in the circumstances to make the premises safe. That duty does not change but the factors which are relevant to an assessment of what constitutes reasonable care will necessarily be very specific to each fact situation – thus the proviso "such care as in all circumstances of the case is reasonable". [Emphasis in original.] The trial judge specifically cited and applied Waldick in his reasons for judgment. He considered the knowledge, decisions and actions of the appellant with respect to the design, construction and operation of the Trials Area of the Park.
 In the context of an extensive discussion of these factors, I do not think that the trial judge’s use of the word “ensure” in the above passage equates to him saying that the municipality became in effect an “insurer” for all activities in the Park. Rather, a fair reading of the passage, in conjunction with the rest of the reasons on duty of care, is that “ensure” means “take appropriate care”.
 Nor do I think that the trial judge’s use of the words “catastrophic harm” means the trial judge improperly inserted the nature of the potential harm to users of the Park into the analysis. In discussing duty of care under the OLA in Kennedy v. Waterloo County Board of Education (1999), 1999 CanLII 3746 (ON CA), 45 O.R. (3d) 1 (C.A.), Feldman J.A. said, at 11-12:
In Veinot v. Kerr-Addison Mines Ltd., 1974 CanLII 20 (SCC),  2 S.C.R. 311 at p. 317, 51 D.L.R. (3d) 533, Dickson J, speaking for the majority, quoted with approval several factors listed by Lord Denning on the issue of whether an occupier has taken reasonable care:
The following excerpt from Lord Denning's judgment [Pannett v. McGuinness & Co. Ltd.,  3 W.L.R. 387] aptly expresses in my opinion the more salient points a judge should have in mind when considering intrusions upon land:
The long and short of it is that you have to take into account all the circumstances of the case and see then whether the occupier ought to have done more than he did. (1) You must apply your common sense. You must take into account the gravity and likelihood of the probable injury. Ultra-hazardous activities require a man to be ultra-cautious in carrying them out. The more dangerous the activity, the more he should take steps to see that no one is injured by it.
In MacKay v. Starbucks Corporation (Ont CA, 2017) the Court of Appeal conducts an interesting examination of when an adjoining private property occupant (tenant) might still be liable as an 'occupier' under the Occupier's Liability Act, where they assumed de facto care over an adjoining municipal sidewalk whereby customers accessed their commercial premises:
 Since it came into force on September 8, 1980, the Occupiers’ Liability Act has governed the duty of care owed by an occupier of premises to anyone who enters those premises. The legislation was enacted following the 1972 Report of the Ontario Law Reform Commission, which recommended that the common law duty of care owed by occupiers, which mandated a standard of care that was more or less stringent depending on why the injured person was on the property (invitee, licensee or trespasser), should be replaced with one generalized statutory duty.
 Section 2 of the Act replaces the common law duty of care with a single statutory duty:
2. Subject to section 9, this Act applies in place of the rules of the common law that determine the care that the occupier of premises at common law is required to show for the purpose of determining the occupier’s liability in law in respect of dangers to persons entering on the premises or the property brought on the premises by those persons. Section 3 of the Act prescribes the duty of care that is owed by an occupier of premises to persons entering onto the premises to see that they are reasonably safe:
3.(1) An occupier of premises owes a duty to take such care as in all the circumstances of the case is reasonable to see that persons entering on the premises, and the property brought on the premises by those persons are reasonably safe while on the premises. “Occupier” is defined inclusively in s. 1 as follows:
(a) a person who is in physical possession of premises, or
(b) a person who has responsibility for and control over the condition of premises or the activities there carried on, or control over persons allowed to enter the premises,
despite the fact that there is more than one occupier of the same premises.
 As the definition makes clear, there can be more than one occupier of the same premises. This includes municipal sidewalks: Bongiardina v. York (Regional Municipality) (2000), 2000 CanLII 5408 (ON CA), 49 O.R. (3d) 641 (C.A.), at para. 20.
 Because the municipality owns the sidewalk, it has the primary responsibility for its condition and owes a duty of care to persons who use the sidewalk. The municipality is not, however, liable for personal injuries caused by snow or ice on a sidewalk except in cases of gross negligence: Municipal Act, S.O. 2001, c. 25, s. 44(9). This gross negligence standard takes account of the fact that it takes time for the municipality to clear every sidewalk in a city following a snowfall or other inclement weather.
 Although occupiers of both residential and commercial properties are often subject to municipal by-laws that obligate them to clear the ice and snow on public sidewalks that surround their property, that obligation is not sufficient to make them occupiers of the sidewalk within the meaning of the Act: Bongiardina, at para. 29; Slumski v. Mutual Life Assurance Co. of Canada,  O.J. No. 301 (Div. Ct.), at para. 5.
 In order to be an occupier of the sidewalk within the meaning of the Act, the occupier of the adjacent premises must have taken steps to come within clause (a) or (b) of the definition, by sharing sufficient possession or control with the municipality. That is what occurred in two often-referred to cases, Bogoroch v. Toronto (City),  O.J. No. 1032 (C.J. (Gen. Div.)) and Moody v. Toronto (City) (1996), 1996 CanLII 8229 (ON SC), 31 O.R. (3d) 53 (C.J. (Gen. Div.)).
 The facts in Bogoroch bear a number of similarities to this case. The plaintiff slipped and fell on an ice patch on the sidewalk in front of the defendant’s Kitchen Table store on Spadina Road, and suffered a broken ankle. The City of Toronto had issued a permit to Kitchen Table to use a portion of the sidewalk in front of the store, constituting about 25 percent of the sidewalk, to sell and display its goods. The trial judge first found that Kitchen Table was in physical possession of the portion of the sidewalk covered by the permit. However, that was not where the plaintiff fell. He fell on the sidewalk in front of the goods on display.
 On the issue whether Kitchen Table was an occupier of that area, the trial judge accepted the plaintiff’s submission that Kitchen Table intended to and did use the entire sidewalk, not just the portion granted by the permit, to sell and display its goods throughout the year, and that the rest of the sidewalk “became virtually an aisle of the store … from which both the general public and its customers could view and buy its goods.” He found that through its policy of aggressive marketing, the defendant used the entire sidewalk to further its commercial objectives, and was therefore an occupier of the entire sidewalk in front of its store, within the meaning of what is now clause (a) of the definition.
 Moody also involved a slip and fall on a sidewalk. The accident occurred outside the Rogers Centre (then called the Skydome) at 10:15 p.m. when the plaintiff was leaving a Blue Jays game. The plaintiff fell on part of the road allowance for Blue Jays Way owned by the City of Toronto. The plaintiff tripped over the raised edge of a concrete slab. The plaintiff did not see the protruding concrete edge because he was walking in a large crowd at the time and had to keep his head up.
 The plaintiff sued both the City and the Skydome. The Skydome moved for summary judgment on the basis that it was not an occupier within the meaning of the Act. The motion judge dismissed the motion. He found that the evidence could support a finding of control by the Skydome over the patrons using the walkway, and thus could support a finding that the Skydome was an occupier of the premises within the meaning of clause (b) of the definition.
 The evidence showed that: i) the walkway was used almost exclusively by Skydome patrons; ii) a significant number of Skydome patrons had no alternative but to use the walkway; and iii) the number of patrons using the sidewalk before and after each game created a crush of activity that made it impossible for a patron to watch for hazards on the walkway.
 The motion judge in Moody also addressed the concern that the result in the case could represent an extension of liability beyond the old common law of occupiers’ liability and the policy that had informed it. He referenced two cases decided before the enactment of the Occupiers’ Liability Act, where the courts imposed a duty of care on property owners who invited a person to use the sidewalk in front of their properties and the person suffered injury as a result: Driscoll v. Breslin et al., 1954 CanLII 141 (ON CA),  O.R. 913 (C.A.), aff’d 1955 CanLII 15 (SCC),  S.C.R. 64 and Snitzer v. Becker Milks Co. Ltd. et al. (1976), 1976 CanLII 594 (ON SC), 15 O.R. (2d) 345 (H.C.). The motion judge did not cite these cases to suggest that the common law of occupiers’ liability continues to apply. He cited them simply to demonstrate that imposing liability in a case like the one before him would not represent a novel departure or be contrary to public policy.