In many instances, police have used facial recognition technology to identify protesters and suspects. Clearview AI, a private company, has collected billions of photos from ordinary people (chances are good you are in their database) and made them available to law enforcement.
Now private activists are building facial recognition tools to identify police officers during protests. Oh the irony. I reckon that the most interesting aspect of this will become the legal side: Building the tools and collecting enough training data is one thing, being legally allowed to use the tools is quite different. I am very curious how this will be decided by the courts.