A lot of the legal things are up in the air still. Basically the FAA is trying to control everything and they have no legal foot to stand on yet.
There is a demand out there but you have to be some what discrete.
It's a pretty easy market break into with these cheap drones. Anyone can buy a cheap phantom with a go pro. It takes a bit more understanding on how they work and how to fix things to really know what you're doing.
There is a lot of rules that should be followed that most people don't even know, flying really high, near airports, crowded areas etc. The blades on even a cheap phantom will fuck you up! I still see idiots flying these really low around their kids
There's a lot of them flying away just because the noobs don't understand how it works and are using crap controllers etc.
As far as mine, I do what I want but I'm bit stupid and flying it near an airport.
As far as privacy, even flying up to a window you really can't see shit with most of the cameras on these things (go pro). A long pole with a camera on it is a much cheaper and easier method to peep.
I have a multirotor thread on here where you can see more details on some rigs.
http://www./forums/showthread.php?t=844392