One of my rules is that kids must be within arm's reach of a parent or the cart at all times. Years ago, the boys got tired of the options of sitting in the cart or walking next to the cart, so they came up with a third option- riding under the cart. This makes the cart a lot heavier to push, but also means that at least one kid is accounted for at all times (and as an added bonus, that child can only see what is on the bottom shelves, so there are fewer "I wants").
Today, N chose to ride below the cart. At one point, Tommy doubled back with a few kids to grab some dog treats, leaving me with the cart and N. As I pushed the cart down the aisle, N asked "Did you get the Pop-Tarts?" I looked down at the cart and said "Nope, we haven't gotten there yet." "Will you tell me when we get there?" "Yes, I will let you know. I know you like to pick your favorite." We continued to chat about what groceries we would buy as we walked down the dairy aisle. I noticed one older gentleman glance at me, look around and then glance back at me. Another lady looked at me a little funny as she pushed her cart past me.
By the time Tommy returned, I started to giggle. Now my husband was looking at me funny. That's when I explained to him that most people couldn't see our child riding beneath the cart, especially once we started loading food in it. While I was talking to N, it looked like I was actually talking to my cart and the food in it. It probably didn't help that I was looking down at the cart as I was talking. This was Walmart, and that kind of craziness is not completely out of the question.