I think the annoying part is that it is clearly illegal under most understandings of the Fourth Amendment but because our legal processes are so byzantine and stuffed full of moldering corpses of prescriptivism past, it's unlikely we'll see any legal recourse here.

The additionally annoying aspect about the question is that this is something privacy advocates have been going on about for years. Ever since I started following the EFF in 2012, they've been warning about the rise in private sector mass surveillance and how it would lead to government CCTV. And now here we are, with Ring doorbells sharing data with LEOs and Flock everywhere.

So to hear 'is this illegal' says to me, at minimum, that a dearth of basic internet sleuthing has been done about this issue and the question was posed out of a complete lack of curiosity and self-driven exploration. Especially now with LLMs, research like this is vanishingly easy to do (as is the adversarial review of it, and the eventual dialectical synthesis). To not do so seems lazy, at best, and that's not addressing how the 'if it's not illegal, it's fine' thought-terminating cliche has been pervasively used to justify detention centers, military black sites, NSA wiretapping, police brutality, etc in a way that seems to universally be a bad faith practice.