Also works for leak detection and runs off of 4G, so no wifi required. 

For example I have a friend that just had a plumbing leak and the home warranty company sent someone out to fix it, they did repair the plumbing but had to cut open walls/ceilings in the process. 

He lived far away and he mentioned that he needed to go to the house and check out a roof leak.

The roof is currently not leaking.  

In my state, there's a 24-hour notice required from the landlord before entry, but in the event of ''my toiled is leaking and I need you to fix it right now" and with the tenant present during the repair, I noticed that the door jamb was damaged as if someone kicked in the bathroom door.

If I'm reading the Illinois Rental Property Utility Service Act correctly, it looks like 7 days is required: "This Section does not prohibit temporary utility shutoffs in cases of emergencies such as gas leaks or fire or, upon 7 days written notice to each affected tenant, temporary shutoffs required for building repairs or rehabilitation." 

You would have to be confident the tenant would a) not turn off the system and b) apprise you of any leaks. 

Your own eyes will tell you a lot... are the walls crumbling, are there cracks in the foundation, are there water leaks on the ceiling, does the flooring need to be replaced, is there termite poop in the window sills, etc, etc.  

Five of six showers leaked.

Apparently, there was a leak roof in a unit that the previous owner was aware of but we were not.