Here is a brilliant idea: a website with an interactive map that shows businesses that are known to use facial recognition. As a bonus, have another interactive map that shows businesses that have gone cashless.

There are sites like this already, but they only list big-chains. It would be nice to know about small businesses as well.

>But how do we know if they are using it?

Employees can anonymously report it. If they see CCTV footage in their store's office and there are white squares over peoples heads, then they can report it anonymously.