I have stayed at an Airbnb that had cameras on the front entry area and the back yard. We were hanging out a lot in the back yard so it was a little uncomfortable, but I don’t think they were turned on. Probably used for security when the house was vacant. It was not disclosed in any way.
@momo2x2018 Cameras facing the bed and live recording?! OMG!
I think I’ll stick to hotels, thanks.
We have cameras at our cabin, in plain sight and just so we can keep an eye on it while we aren’t there (there was a squirrel incident). We don’t rent it out but when our kids go there with their friend the first thing they seem to do is turn the cameras towards a wall! Cracks me up every time.
Pulling this thread back up to post an update and express my thanks for the helpful input. The host posted a lengthy response on Airbnb to the review that concerned me, explaining his camera policy in depth, so future guests will know what to expect. We saw no cameras other than those at the entrances.
I think our Airbnb days are over, though. There are just too many things that can go wrong, as the Atlantic article @somemom linked shows. This time we found that the house was exactly as pictured, but the location was substantially misrepresented. I can’t say I trust the review system at this point. We’ll continue to use rental houses for family gatherings, but not through Airbnb.
A note to all readers:
Expedia bought VRB/Homeaway, for literally billions. In 2015 and immediately began adding huge booking fees, previously there had not been booking fees, instead owners paid to be listed (up to $2500 annually.) They are still changing the owner fees all the time to maximize their income.
When you are looking for a home rental on VRBO/Homeaway/AirBnB/Trip Advisor, see if the owner has named their home, then google the house name and owner name and see if you can find their website to book direct.
There are thousands and thousands of homes available and probably only a small group who have gone out on their own, but the owners I know in my book direct groups are all very good.
Thought of this thread when I read this today –
https://www.cnn.com/2019/04/05/europe/ireland-airbnb-hidden-camera-scli-intl/index.html
Gives a new meaning to a “room with a view.” 
I’ll continue to stick with hotels - although I don’t assume privacy can’t be invaded even at the best.
This one got a lot of publicity
http://www.mysuncoast.com/2019/03/29/airbnb-renters-find-hidden-camera-inside-fake-smoke-alarm/
Oh, and in Korea, the cameras were in hotels and motels. https://mashable.com/article/website-secretly-livestreamed-hotel-guests/#vG4pS532mPqT