Questions asked, No-one to give a real answer
Follow that link. Read the forum and you will see some partial answers to the posters question but no full explanations. Sometimes I have to wonder if it's even worth trying to explain why we have to do what we have to do. In essence the original poster is trying to look at one aspect of the auto service industry, and then attempt to force it into his own vision, by changing the rules after the fact.
As you read through notice in one response it's the shoddy work that was done, and they left the sun roof partially open. That is assuming that at the worst the switch was inadvertently bumped and the tech didn't realize it, or maybe the OP or a relative simply didn't close it themselves correctly. The same line also says "they must have been joy-riding around", because the rear seat was pulled loose? Again assumption, and easily falsely accused. Now the OP also mentions wires hanging down. I've encountered situations where aftermarket installed equipment makes it very difficult to perform the ordinary service because of all of the spaghetti that is simply tucked up around the column. Most of the time the factory wiring is quite neatly held and cannot fall into a drivers feet. Does it make it right if that happened? Of course not, but it would be interesting to see exactly what was being referred to. Then in another someone claims that when they had found someone that would install their carry in part for cash that they had finally found someone honest. Note, paid in cash, probably no reciept, no income claimed, and/or appropriate taxes paid,, yep,,, that's honest,,, yea, right.
Now the whole thread alledgedly starts because of a verbal quote of around $220 to fix the turn signal and the final price was $260. I would be extremely suprised if someone like the O.P. would ever get into my shop these days. We don't guess prices over the phone. We would start out with a diagnostic fee, and then advise him (written estimate) from there, but he probably would not be happy with that approach so he would go to whomever guessed lowest first, reguardless of what the final price would be.