And that is why you only ever take cars to a dealer/garage/detailer as a last resort ... and if you do take them take them to a independent specialist with links to the owners club.
Bit of an over reaction I suggest.
Have you read any of the owner forums for the "decent cars"?
Garages and other places taking cars for a joy ride is nothing new - not in UK, not in USA and so on.
If you want to read some stories (from USA though), look at NASIOC (scooby forum) - some of the stories there will make you cringe - garages that are simply meant to be doing alignment (which does require a test drive) taking a scooby for a test drive and writing it off at speed; another place that was doing BODYWORK doing WOT runs and launches in their car part on a modified scooby from a cold start.
We also have this gem (a Legacy that happened to have the camera automatically activated)
I can go and find the same sort of stories from UK owner clubs if you want
I don't tar them all, however as I said if you are going to take it somewhere take it to a place with some links to the OC
doing alignment (which does require a test drive)
What?
I took my car into a garage on Sat for alignment, the only driving they did was from the parking area out the front, to the alignment machine, and then back out to the front parking area. There is NO need for a test drive with alignment.
If you think that guarantees better service you are again misguided.
If it's been set up correctly there should be no issues of pulling to one side or other, that's the point in it.
How so? A garage that gets a lot of custom from a certain car owners club would want to keep their name in good standing there - as opposed to a garage who just gets random people from local area coming in meaning that them having a bad name on say mr2oc has no effect on their business.
My point........"THE ARE NO GUARANTEES!"
There are plenty of good independents out there that have sod all to do with owners clubs and there are plenty of owners club members who have had poor service from well know 'aproved' garages. You asked if I had any experience and I would say compared to yourself my experience is vast having been a member of many well known owners clubs and forums for years and having owned a few nice cars that I have had serviced without and with issues.