Everyone seems concerned about what it could be doing, not what it is doing.
I could sit next to a vending machine and make notes on the gender and sex of each patron for demographic purposes, nothing would be illegal.
Why? Well, that's easy, I want to stock my vending machine in order to make money. Instead of testing different layouts which would take a lot of time, I could predict how well certain stock would do based on preexisting market research.
This appears to be just that, but with a camera.
Now, you can argue "but it could be worse"! That's not a valid argument. It could always be worse for things you don't know about. If it holds up to be true, as stated, it's just what it is.