A family friend's Mercedes E500 brakes stopped working on 280, and he had to shift the gears down and pull over to the side (this is back in the early 2000s). He brought it to the dealer, and something along the lines of the dealer claiming they couldn't see a record of electronic failure in the logs, then refusing to give the car back to our friend.

He only got the car back when he engaged a lawyer to sue the dealer. The lawyer was happy to work on a contingency since "we have no chance of losing this one in court".