I guess those are all very valid questions/concerns, but that's why I love technology; this may not be in our hands dirt cheap next week, but I am very curious to see where this (or other sensing tech) is going to be a few years from now.
I mean, I just found a "radar" sensor unit for about 50 cents that can be hooked up to an esp8266 and do presence detection while completely hidden out of sight.
Another thing is what about actuators? Amazing if it can detect a dripping faucet, but instead of notifying me, please just stop the dripping
Anyway, I am very curious where this will go..