This may be a moot point, but someone awhile back asked what one needs to do to be an Airbnb host. I am one, and the answer is "not much". You list your space, take some pics, and you're good to go. Your listing definitely needs to be approved by Airbnb, but unless it looks horrible or you don't provide enough information or...whatever other red flag they may find, I don't think there is a huge vetting process. However, I don't think this has anything to do with Airbnb. First, she lives in the same town. I doubt she would have reserved the space through Airbnb to stay 20 minutes from home, and if she had, there would be a clear record of it. All guests and hosts, once the reservation is accepted, get the other's information, so it's all out there - and of course Airbnb can pull those records any time, too.
I am curious though, if the maid saw all of those cameras you would think that any Airbnb guests would have seen them, too - that's assuming that he ever had any. I put a lot of work into my space and am almost always booked with tons of easily seen great reviews, but it's work. You have to really take care of your space and your guests, and I'm not sure this guy would have done that. In any case, visible cameras are defintely a big no no and should have been reported, if he had any guests that had seen them. I know I sure would have reported it! I have stayed in quite a few myself and would have never not reported something like that!