I did one of these a few years back and the salesperson would NOT let me leave. I spent over 2 hours in the store.
When I did my report, all of the requirements had been met; all of the necessary questions/answers, etc....and I was able to give great detail about the sales person keeping me for so long, even though I tried to "politely be done...." The MSC apologized and gave me double pay, which was unexpected
That was just an anecdote ^^^ but other than that, I've done them pretty often and they are easy and seem to pay okay