Hence the "warranty" that they mention and usually it pretty much is that. So its a race to zero, and the best to even consider this is bitcoin you gotten through profit.
Shared codes is an issue for sure, especially with these cards but that wasn't the issue with these (and all "similar") Panera cards, These were locked by Panera with balances on them. According to local store manager stores will not take cards showing purchased before a certain date unless you can prove ownership and legitimacy. Many of these cards had numbers off of physical cards that were never sold so it is obvious how they were obtained. If someone wants to take a chance and fight with the store manager you might get a free meal out of them which was what happened to me but their terms (just like Starbucks and most others) state only cards directly purchased from them are valid so that is their excuse for not taking them. I assume if someone takes them to court they might have a chance but I highly doubt folks who paid anywhere from $6 - $15 for a $100 card would want to do that for obvious reasons.