I'm guessing almost no one will quit. Some will get it, many will upload fake cards which AA will not investigate because it is not in their interests to do so. Either way, it's nothing to make light of imo, many of the side effects of the vax (myocarditis, blood clots/TIA, lightheadedness/reduced consciousness, etc. etc.) that have been documented will permanently and totally prevent you from getting a first class medical if disclosed honestly to your AME. No provision is being made for people in this situation. I guess they could sue AA maybe, probably not though since they had the option to "just quit" and therefore weren't forced.