Is this a black market thing?
One of the silliest things I’ve ever seen Is someone walking around with an enormous cup, and a stupid “mine is bigger than yours” blank stare on their face. Dragging something like that around all day is one of the stupidest things someone can do.
https://www.today.com/food/trends/stanley-cup-craze-rcna132901
Sorry about the source but seems to be the best explanation,
Most likely they got ahold of them or had them set aside before being put out for sale.
If they were out on the shelves, and the store had been open for a reasonable time, then this is ridiculous, but then it would likely have been a lot more than 7 workers.