I've never been ripped off badly but my wife would get taken advantage of before I met her. Nothing huge but always getting upsold on tick-tacky stuff. New plug wires installed way too often, etc. It really pays off to understand enough about car maintenance and to speak clearly about what you want inspected (not just "it's making the noise") to keep the shop honest.

Once I went to drop my brother's car off at a body shop for him and I just assumed I could whip it down there and leave it but they made me make an appointment and bring it back. He was out of town so I took it home and kept it until the day it was booked in, then I had to drive it ALL the way down to the shop. Just terrible.

"Friend" of the family was the mechanic at a local service station. Would give me what I thought was discounts.

In reality, after a few thousand dollars, he made a comment to a fellow workmate "That he didn't know why I kept bringing the car back for work. It was a bomb and I should've gotten rid of it years ago". He however was quiet happy to work on it when asked.

Didn't realise I overheard the comments.

It took a couple more of these sorts of incidents before I stopped trusting people in general.

Edit: First car when still in high school early University.

The dent came back a year or two later. xD

Pretty much any auto repair shop falls into the same category, especially dealer repair shops.

I rebuilt a old cj5 Jeep and had a body shop spray it . They had a kid put sanding marks in a hood that was already sanded and primed and then sprayed fish eyes and runs all over the interior. I also never got the clear coat and was to young and dumb to know It.

Mechanical tech here, not a body tech, but if I were to do work on a specific component that had multiple sensors I would absolutely need to disconnect every single one to avoid any damage, which might happen anyway because the electronics these days are so goddamn sensitive. Also there is airbag bullshit in there. I would of course inform the customer of this before doing the work. Scanning the system at the end sounds like an appropriate measure, as I wouldn't want the customer to have problems a thousand miles down the road. We have to deal with that shit every time we do a simple alignment now because of the lane departure warning systems, adaptive cruise control, active braking, etc... We won't even align Teslas because of the liability

My advice would be to research what goes into an actual fix on your vehicle, as the systems get more complicted every year, and therefore the price of the fix rises. I'm sure it's ploy by the manufacturers to charge more for their services, but it ends up making us all look bad.

Look around for an earlier model car that doesn't have all the computerized bullshit installed and your repair bill won't sting so badly.