'Ex parte' refers to a court appearance where there is no notice given to another party, for whatever reason. When you do, the law requires that any evidence provided be 'full and fair'.
. Misir v Misir
In Misir v Misir (Ont CA, 2017) the rule about evidence in ex parte motions is set out:
 A party who seeks relief from the court in proceedings without notice is obliged to make full and fair disclosure of all material facts. This is a common law rule that is enshrined in rule 39.01(6). See also Sangster v. Sangster, 2003 CanLII 48248 (ON CA),  O.J. No. 69 (C.A.), at para. 7. It is unnecessary to find that the court was deliberately misled before a court will set aside such an order. The basis of the rule is fairness. As the rule confirms, the failure to make such disclosure is a reason, in itself, to set aside the order made: Mariani v. Mariani,  O.J. No. 1464 (S.C.); Balanyk v. Greater Niagara General Hospital,  O.J. No. 4867 (C.A.).
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