I had a friend who worked at one of these fast motorists centres and quite disturbingly they had to meet targets to keep their jobs,. when a car was brought in for an exhaust they had to tell the customer their shock absorbers needed replacing or brakes relining, more disturbingly they were given a squirter with old brake fluid and were told to squirt the stuff on back plates etc. then go and get the customer out of the waiting room to show them the brake fluid leak. They were encouraged to target women with children who were considered much more easy targets.
They were told their wheel bearings had gone which had caused the brake problems and new whell bearings would be required (which were not fitted, discs needed as well as pads anything to boost their targets they had to reach.
This shocking behaviour was a few years ago but I have no doubt little has changed apert from they can now use a computer to rip you off and charge you diagnostic fees and a fortune to turn service lights off etc.
