I am somewhat on the fence on this one, which is not all that unusual for me. I have been around machinery and mechanical stuff all my life with great risks, so things like this bear little danger to me. Neither am I for or against from my thoughts to what I can tell. The risks I do believe are minimal if hardly any at all.
The biggest thing I see is a person's perceived privacy. Notice I placed this at a person's privacy level for the conversation. Where I do think there is an issue is how my conscience would play out if I did this. If for any reason any aspect of what we do in RC becomes a possibility of crossing a line we may be best putting more thought into it.
Please don't read more into this as there must be a baseline set for thinking this out properly. There are those of us that are more risk takers than others so that adds some variables into the baseline and then we must have rule makers because we need governing. I guess I am one of those guys that follows more along the lines of when in doubt think some more about it and make sure you have all the angles before making the choice.
Is it safe? I would think it is about as safe as you can get when comparing to all the other RC planes I have seen fly and get away from folks. I have seen RC planes of decent size just fly off into the sunset. Fortuneatly to never see again and yet in some cases they were found. Can you imagine had those hit someone, hit a car windsheild, or fell into a crowd of people? Yes, they were flown from an AMA RC club!
I don't know anything about your town, but I wonder since it is legal to fly the way you are what would be the harm in letting folks know your ''route'' and that you will be doing such flying and making them aware that you really cannot see anything down low that would cause any privacy issues? Is that out of bounds? It certainly would be respectful and courteous and if someone said ''No'' then you could alter your route to accomodate and that would give them the choice?
On a side note, it would not bother me for a park flyer to fly over my house at all - day or night. I think privacy is a sensitive issue now and that changes the game somewhat. I really don't care as long as there is nothing that I deem a privacy invasion. When I am absolutely sure that a privacy invasion has occurred then I would take the park flyer out by whatever means I could find to do so [X(]