The secret shopper idea is interesting. For what it's worth, I have some experience with that in the restaurant business. My first secret shopper caught me by surprise, but after that I knew what to look for, and I could always tell who they were right away. There were a number of "standards" I felt were stupid and didn't follow--not health and safety stuff, just rules about pushing alcohol and appetizers (although I know some people did skip over health standards as well), but of course I did those things in front of the secret shoppers. One restaurant I worked at gave up on professional secret shoppers and instead used people from the corporate office, who knew the rules more fluently and didn't obviously check their watches every time the server came to the table like a bunch of morons. I think to make that idea work, you'd need very experienced divers, very familiar with instructional standards, who were also good enough actors to look like noobs. It would be expensive, but maybe doable.