Commies.I didn't even know one could set up a guest AP.
Not that I plan on letting any guests use my WLAN any time soon.
Here, it's enabled as a default in most big ISP supplied modem-routers. Part of their marketing scheme (come with us, leave it enabled, and you can connect from anywhere if there's another subscriber around).
I don't mind - or rather I didn't mind even when I was living closer to other houses. The system is set up so that your private access has bandwidth priority.