Sometimes being trapped is just fine. However, if it's not, my spouse and I have an SOS agreement, where the other will go to the kitchen and rattle the treat jar. Cats get treats, it's their decision to get up, and we can make our escape. Win/win.
One of our's is mostly white and we're pretty sure he has some deafness, too. But he can still hear the treat jar as long as we rattle it loudly enough.