The problem here is not a gift card, the problem here is shoplifting. Naturally Petco does not want to repel gift card customers just because they cannot catch

The problem here is not a gift card, the problem here is shoplifting. Naturally Petco does not want to repel gift card customers just because they cannot catch shoplifters. Once shoplifter succeeded - he can sell stuff on eBay, on Craigslist, via gift cards or just directly on the street. Gift card is just a convenience vehicle that Petco agreed upon to keep opened regardless of where merchandise came from. In fact many stores do ask my ID and address/phones numbers before accepting returns. It's hard to make millions with this type of theft (not fraud) model. After 3-rd return without receipt - pretty much every store will kick person's butt out of the store or call security/police.