Here in Dublin we've long had what are known as "lockhards". Their scam was to "direct" you into a free parking place, then ask for money to "look after" your car. Of course the implied threat was that if you didn't pay up, who knows what would've happened to it...
There are a lot fewer of them now since the city centre is all paid parking, but I did see some outside the Mater Hospital a couple of years ago!