An exception to the law of trespass is that an owner of goods is allowed to enter another's property to seize goods which are there through no fault of the owner of the goods. Reasonably necessary force may be used to reclaim the goods if the person took them wrongfully, or if that person knew someone else took them wrongfully [Huet v Lawrence(1948) QSR 168].

This does not allow a careless child to retrieve a ball that is there through the child's fault. Similarly a lender of goods cannot use force on the borrower to get the goods back, because the borrower did not acquire the goods wrongfully.