Kira Witkin in Esquire: I Got Paid to Spy on People While They Worked. I know a lot of people that work or have worked in retail and more than a few have been fired after failing secret shopper tests. I’ve never considered the other side of the story though.

The average commission is $15 to $20 per assignment, and assignments can require several hours of work. Cutting into shoppers’ bottom lines, evaluations are sometimes rejected due to failure to comply with technicalities, like ordering the wrong item, arriving even one minute late, or omitting a required photo. Cassandra Tulloh, a mystery shopper with eight years of experience, once had a bar shop rejected because she “didn’t get the correct details”—sticking her with the $85 bill, despite sinking hours into the shop and write-up.

It’s an eye opening story. Retail workers (low and minimum-wage earners in general) are some of the hardest-working and least-appreciated people around.