Really... is it so hard to imagine? Criminal gangs can put tiny cameras everywhere to track the police but the police cant do do the same to them.
If I am not under investigation I shouldn't be monitored end of discussion.
If I am under investigation, then if my case has not reviewed by a third party (judiciary power/judge) then I also shouldn't be monitored.
It's basic human nature. Without checks and balances those who can abuse, will abuse. It doesn't matter which side they are on.
Property owners doing so on their own land is a whole different matter.
I just don't see it happening at a widespread scale yet. On the other hand if you give police the right to use these technologies you can bet you'll see police (and other government agencies piggybacking off them) deploying this everywhere very fast.