[userbinator]

I'd say that if you're renting to someone else, it's still your property so you should be free to monitor it, but not disclosing the presence of cameras or other monitoring devices should be illegal.

[17760704]

Ownership is a bundle of rights. In the U.S., if you have rented out a property you "own" to another person, you do not have the right to enter that property without prior notice or consent of that person.

[dheera]

Again, legality aside, even if it were legal, I'd say it's unethical to do so without consent or at the very least, prior notice.