Besides those who intend to scam you and those who are selling you GC without proper explanation of how they aquired them, that might be a pretty small group.
You are definitely right about this. Only a pretty small group is legit.
Maybe one lesson could be not to buy GCs without proper reciept, and leaving out on those deals you can safe too big, for obvious reasons.
This is actually something that I don't quite understand. If someone carded some Giftcards illegally, wouldn't they still have the receipts for the transactions? How would a receipt help in this case? It is not like there is somewhere I can look up the credit card he used to buy the GC is a stolen credit card or not.
Secondly, if someone received some GCs as gifts, lets say over Christmas. Wouldn't they be the ones that not able to provide receipts?
Leaving out on deals that I can save too big is definitely a good advice.