A man who ate free for a year buying a refundable ticket, accessing the China Eastern lounge in Xi’an, China, and the refunding his ticket. Every. Day. There can be consequences to this scam: Lufthansa sued a passenger and won 200 euros after the man booked and cancelled 36 tickets in a year for the purpose of obtaining business class lounge access.
Another passenger was even arrested after living in 9 different Priority Pass lounges at the Singapore airport over the course of 3 weeks.