I'm sorry? It's DANGEROUS to have a child use a shopping trolley??
It's dangerous to get out of the bed in the morning, too, there could be a banana peel waiting for your unsuspecting foot.
What I'd be concerned about is the "consume early, often, and in excess" message that "shopper in training" trolleys send.
But this is the age of the "magic" plastic cards and weekly "allowances" to ten year olds that could keep a family of five (in certain parts of the world) fed.
That's right, the apocalyptic riders have given up horses, they're riding shopping carts now.