Ways to trick your baby:
Problem: You need food. This means you have to go to the grocery store. This means going to a place with forbidden goodies hanging from every nook, cranny and crevice, with a strapped-in, mildly annoyed to threatening-to-blow toddler. For an hour. While you try to remember what's on your shopping list.
Solution: Find something boring that you're already going to buy that the baby can hold while you shop. For us, it was a big cheese block - one for each baby. I always hit the dairy section first and even by that time the twins are reaching for various treats (usually in glass containers), so I pick out a few blocks of cheese, make as if to put them in the cart, and then, instead, hand them to the children. They are gratified, study their haul, and we can move on. When the magic of the cheese wears off, we're usually in the pasta section, and I switch out the blocks for pasta which the babies can shake endlessly.
Ways your baby can trick you:
Problem: As your kids get older, they're going to need something a little more stimulating than a cheese block. At this point, they know what cheese is for, and they have the teeth to do it.
Can you see that? The flash makes it hard. That's a hole chewed through the cheese wrapper and a chunk eaten out of the cheese. First, how awful that my babies were sticking something in their mouths that's been in who knows how many people's hands while I ignorantly perused the seafood section? Secondly, try explaining to a cashier that, yes, that's your cheese, and you let your kids do that to it. It's uncomfortable.
Solution: Bring a few toys your child hasn't seen in a while in your purse when you go shopping. When you're searching through the foodstuffs, and they start to get restless, you can give them their own toy as a treat to play with while you shop. This will only work if they really haven't seen it in a while, though, otherwise, it's old news. If you're still going to choose something from the store itself, my advice is make a better choice than thinly wrapped cheese.