I'm going to ignore the $17 fee because I know of nobody who will do it for such a piddly amount.
Our mystery shops are part of the ongoing training sales associate receive. We identify weaknesses to be addressed and associates get rewarded for good performances. Anything helping an associate improve their performance helps them make more money. You can't work under the assumption everyone who walks through the door will become a paying customer. It is far from the reality. As mentioned previously in this thread, we should visit at slow times and make a point of keeping our shops as short as reasonably possible within the guidelines provided by the client.
Equal rights for others does not mean fewer rights for you. It's not pie.
"I prefer someone who burns the flag and then wraps themselves up in the Constitution over someone who burns the Constitution and then wraps themselves up in the flag." -Molly Ivins
Never try to teach a pig to sing. It's a waste of your time and it really annoys the pig.