At the end of several affairs, we notice that there are some cakes and pastries which are completely untouched. The caterer says that, by law of the health department, once a cake is out of its box, even if it is untouched, it must be disposed.
Is it considered, then, a mitzvah to take these cakes as we know they will be disposed (avoid Bal Tashchis)? Can we assume that once the cake is displayed, the owner assumes that it will be eaten, so he has relinquished "ownership" of the cake? The fact that it is untouched or even partially touched is incidental. Or do we need to assume that the owner may want all the leftover cakes himself, in which case taking anything would be considered stealing?