While it can occur anywhere in contract (or even other) situations, the legal topic of 'deposits' is not actually contractual in nature. It is a separate "ancient" doctrine dealing with 'incentivizing' parties by means of a security device to perform their obligations.
That said, deposit issues arise a lot in contract situations - especially real estate conveyancing situations - likely because more real estate court cases are pursued further in the courts given the large quantum of dollars involved. Interestingly, real estate cases also tend to increase when the real estate market suffers a downturn and speculative purchasers want 'out' of their respective deals.
