I have been doing some HP reveled shops. Not too bad as I just show the authorization letter when I go in and have had no issues. Also an added bonus is the company pays you in US$ even though in Canada which is a 30% bonus for us here.

I haven't but I often wondered whether I should. lol

I have done many gas station revealed shops and audits. I do not mind them at all. The only thing I hate is when the manager or other employee gets anxious and makes you wait while they call a higher up. I always have to explain this does not require me to see records or anything of a personal nature, but they get paranoid. I had several ask if it will damage them in any way if they say no, some have asked if I can return when a manager is on duty, and one lady started crying!