Same goes for home cameras doesn't it? There is no way for individuals caught on camera to protect their privacy, there are no signs across the street saying you are under camera supervision, no protection from invasion of privacy? True, police cameras go places that are private, but then we expect (though probably don't have rights to) privacy driving our car down the street, or even stepping onto someone's private property for legal reasons.

> no protection from invasion of privacy ... then we expect (though probably don't have rights to) privacy driving our car down the street

That's the key difference. In the US, public places aren't generally afforded any privacy protections and thus video can be recorded and shared. Police go many places that aren't public, so a significant portion of body cam footage is likely illegal to share.

Of course in this particular case (Ring live streaming) there's a question about whether it's legal or acceptable for police to engage in such practices on a wide scale. An end user doing something once simply isn't the same as a large government agency doing it many times over.