As it stands they're $20 on Amazon with dozens to choose from.
Nobody's calling for outright banning of cameras. It's about the way these and their feeds are being deployed, integrated and utilized.
If the cop used an unauthorized GPS tracker without a warrant, you could take them to court for a Fourth Amendment violation and stand a pretty good chance at winning.
Even if you want to argue it was done purely as a personal citizen vs. citizen matter, you could almost certainly win a lawsuit for harassment and stalking.
There's plenty of precedent for both types of cases.
Flock cameras are stalking at scale, and they should not be tolerated.
Neither "make the device" illegal, but they do make using them for the designed purpose illegal. In the same way owning a sawzall is legal, but using one to cut down all flock cameras in your town is illegal. As it stands, they're about $100 on Amazon with several options to choose from.