Agreed. I've trained my cats to come to a bell, because it's easier than finding them when it's vet time. I found a bell that's loud enough to be heard across the house, and I ring it before giving them breakfast/dinner and before any treats.

One of them doesn't come consistently, but that's because she only eats when she's hungry and doesn't really care about treats. She's also not the problem child, so it's not a big deal.

The problem child, however, has recognized the bell, and is trying to find other ways to make a bell sound when he's hungry.