Nearly three years ago the story went viral about a man who would buy and refund an airline ticket each day using that ticket to gain lounge access and eat free for a year.
Two years ago a man did this 36 times with Lufthansa’s lounges and they sent him a bill for 2000 euros. Airlines often have requirements in their contracts of carriage saying that you actually have to intend to fly when buying a ticket and this sort of behavior is highly suggestive that the man never intended to actually fly.