I have heard of a guy who was a real p.i.t.a. to his mechanic (numbering tyres to check if rotated, etc) - the mechanic retaliated by loctiting the plugs into his 626. Guy took mechanic to court and won.
This is what I don't understand with mechanics. You are entrusting them to take care of your car not to mention paying handsomely for it, but they resent the customer taking steps to try and make sure all work requested has been performed -something often difficult to do -and we get low mongrels like this. ExÍŸaÍŸcÍŸtÍŸlÍŸy why they need to be checked on in the first place.
