[ptd]

I don’t believe there are laws prohibiting video surveillance in public by businesses. Some states have laws prohibiting filming in locations where one expects privacy. Other states allow filming in private spaces as long as the business notifies employees and customers they are being filmed.

[SolarNet]

Yea most states also have a pretty clear "if the device is obvious" law. It's also why businesses put up "smile you are on camera" signs, especially if their camera isn't immediately recognizable.