This really annoys me , garages let young lads adjust the track on cars and they haven't a clue what they are doing , I,ve been in the mechanic game for years and always prided myself on getting things right , the trouble is , is that wheel alignment has no guarantee and garages know this , they can align your car and as soon as the car pulls off the garage front that's it , you could of bumped up a kerb , hit a pot hole and its gone out . The mechanic should always do the alignment before removal of the old tyres , this ensures the suspension does not have to settle after being jacked up , there should be a steering wheel lock fitted while its being aligned which clamps the wheel straight using the drivers seat , the readings should be taken from the gauges to the rear flags and the adjustment to be made worked out from these readings , unfortunately many fast fit garages think that parallel will suffice for all cars , its not good enough , they have charts and tech data available but unfortunately most of them cannot read lol.