I did a reveal shop for a "Crab" restaurant. The reveal was mandatory regardless of success. I was a bit uneasy at first since they failed on a few levels. When I returned with the results (you have to speak to the manager) I just emphasized the good and ignored the negative. They required that if they ask you for details you instruct them to contact their regional mnager. It was a lot easier than I thought it would be (I hate confrontation).
The reveal if they pass shop is the best. Most of the time the parameters are so hard you never reveal yourself. If you do have to reveal it is on a positive note.
Good luck. The first one is always the hardest!.