Just that really.
Never allowed my DC to do it.
I think it is gross that some guardians allow children to sit amongst the groceries in the supermarket trolley.
Makes me shudder that they could have dog shit or other unmentionables on their outside footwear. This would contaminate their shopping and the next unsuspecting persons. I also think it's dangerous having a kid hanging off the edge of a trolley. Pisses me off to see this. Am I alone?