But "taking a photo of me on the pavement" doesn't sound like "fixed installations"; it sounds like me as a tourist not being allowed to take a snapshot of a picturesque street just because you happen to be standing on the pavement.

I think I wasn't clear enough that I was referring to the nest camera the parent was talking about.

Ah, yeah, good. Because I've taken quite a few snapshots when I've been out and about, always under the impression that what I was doing was perfectly legal. :-)