In one instance I watched the craft at low altitude go around several buildings in a way that it would have been literally impossible to draw a straight line to ANY point without going through one of the buildings. That's the only instance I'm 100% sure.

In other instances me and several members of our community literally went around trying to find who the hell was operating some drones over their properties (because they were dangerously close to some fragile things), and no one could find them. So possibly had some line of sight, but were pretty darn sneaky.

Operators aren't necessarily stationary, and there isn't necessarily one operator either.

Very true, though they generally cannot easily walk through concrete and fences.

You can't legally be moving and pilot a drone according to part 107 though if you're hobby flying it technically might be allowed but it's hard and not a novice thing too do since the RTH needs to be updated as does time left.