Inspired by this question, if the holder of an object tries to place an object in the pocket of the shadow clothes (those created by the spell shadow conjuration), the object automatically succeeds on its saving throw to disbelieve, and the clothes are only 20% likely to affect the object. So 80% of the time, the DM determines what happens, but I suspect that means objects fall through the shadowy pockets as a wearer tries to place things in them.
Objects (excepting magic items) only sometimes receive saving throw rolls. Unattended objects get no saving throws, but attended objects often "save as the character [holding them] (that is, using the character’s saving throw bonus)."
According to the SRD, a creature can "voluntarily forego a saving throw and willingly accept a spell’s result."
So, can a character holding an object forgo the object's saving throw, so as to allow them to place things in their own (shadow) pockets?