I had an employee that stole a bunch of cheese and pastrami (I know, right, what's the point of stealing $50 worth of cheese and a block of pastrami?) inside empty pickle buckets he was "taking to the garbage bin" but really took to his car's trunk until said cameras were installed. A couple weeks after camera installation and a couple weeks of my eyeing him suspiciously, he quit saying that all the changes were annoying him and that the cameras were the last straw.
Currently the employees don't even dare to shift the blame for things that go wrong - not to mention I try to cultivate a culture of just being honest with me and giving people a pass for most offenses. They really seem to believe that I'm watching them when I'm really just occasionally checking the cameras for activity at night when the restaurant is closed. I think it also helps that I'll occasionally use the camera and the footage being recorded when a customer is being an asshole - to support my employees.
While I hate the idea of surveillance especially en masse, it seems like certain groups of people are willing to be a lot more honest and hard working when they think someone is watching and when it helps them too.