Ummmm . . . keep them sitting down!
Was in a store not too long ago in a check out line and a toddler and his mother were in the next line. The toddler kept trying to stand up in the seat of the cart and reach over and play with the carousel that holds the plastic bags. His mother kept telling him to sit down but was caught up in paying for the groceries. All of sudden there was a "thunk" and the toddler was screaming - he had fallen out of the cart on his head! And I seriously don't think that the dimwit mother probably even took him to the emergency to have him checked out. I don't have kids but there are situations in which a child can be seriously hurt (even killed) in the blink of an eye - allowing your child to run through a parking lot is another example. Hellooooooo . . . ?!