Many mystery shoppers are uncomfortable with the idea of doing video mystery shopping, but two major advantages are the pay (typical is $25-$50 per shop, and it can go as high as $100 for a very complex shop), and the fact that in most cases, the video you have shot is the shop report, so paperwork is minimal post-shop.
Shoppers who have concerns about taking their "secret shopping" to a new level can be reassured by the fact that most employers who undertake these programs understand that they can be audio or video recorded by a mystery shopper under their employment agreement. The employers then use this tape to provide further training to their employees. It can also be included in their performance evaluation. Of course this makes both the shopper and the client highly accountable.
This last part is something to think about. Not only is everything the employee does captured on video, it is also very obvious as to whether or not you conducted the shop according to guidelines (although your proof that you did it right is also on the tape in the event of a dispute). But suppose something happens to your "proof". I always say technology is great...when it works. The downside of audio or video mystery shopping is that technical difficulties can occur. If you forget to turn on your recorder, the battery dies, the focus is off, etc., you may not be paid for your shop.
Overall, for experienced shoppers who are comfortable with the idea of using video equipment in their work, it looks like it could be a good way to earn higher shop fees than the norm with less paperwork. I advise newbies and beginners to wait until they have many shops under their belt before they attempt video mystery shopping. They first need to be very comfortable with "traditional" mystery shopping, and can pull off a scenario with ease, before they add the distraction and complexity of concealed equipment to the mix.
Jordan, Melanie R. 2002. <http://www.homebiztools.com/ideas/video-mystery-shopping.htm>.