[ars]

What stores? The only stores I know that do it are Walmart (sometimes) and Costco and SamsClub (always).

Costco and SamsClub don't give you bags, so that would be my guess on why they check it.

I've lived in the US for many years and besides those stores I've never had to show a receipt (that I can remember).

[petercooper]

Ah man, I can't remember all the stores I've been in while on vacation ;-) But yeah, definitely Walmart, and another I remember in particular is Fry's.