I worked at a fast food restaurant at the mall in Erie, PA when I was in high school. Pennsylvania has no sales tax on clothing (or at least that was the case when I was in high school). So Canadians would often drive down from Ontario to do their clothing shopping.
It was not unusual to see somebody walk into the rest room with their bags and walk out wearing new outfit. Sometimes they'd toss their old clothes in the bath room.
You could also tell the vets when they paid for their meal. Store policy was paper currency had to be converted. Change was taken at face value. So the vets would pay for their meals with piles of Canadian coins