There is a small OTC medical device that is about $60 in the US, quadruple the price in my country. I tried to order one to be sent to a US family member's house, who was coming the following month to visit. However I could not order because I was not in the US.

In the end I found another online store, paid $74, and got the device. So the better store lost the sale due to blocking non-US orders.

I don't know how much of a corner case this is.