Or worse - the ones who simply abandon their trolley and wander off to find things in other aisles. Allegedly, I may have been known to add random goods to their trolleys...
Made worse by the narrow aisles so many supermarkets seem to prefer here - some of the nearest ones to us are actually difficult to pass two abreast in without paying careful attention.
I knew a guy, who if he came across an "abandoned" trolley in his way, he would put random products in it!
If it was in the right isle he would put embarrassing ones in it.