You don't play a plausible deck because you need several accounts to make it work (6 if you want to do it quickly), and you don't want to spend 100s of tickets on decks when you could spend 2.
It should be trivial for WotC to catch people doing this by looking at their match history, regardless of what decks they're running. Someone running this scam is going to be paired with a cyclical group of players over and over again, which would be impossible for a regular player.
If it makes people feel any better, this doesn't affect league results or prizes for any legitimate player. It's effectively like someone telling WotC they ran an FNM to keep the WotC-provided foils.
Vintage players should just keep it in mind when they make decisions based on published decklists