I had one of those back pressure sewer valves put in $500 installed.It made a BIG difference as the insurance co didn't want to include coverage as the home had a claim in the past (b4 I owned it, & the city sewer backup was not the fault of the home owner).In my area if it happens you're responsible for the temp accommodation of the tenant(s) until it's cleaned up.Since then the only blockage we had was viewed via camera & found to be a city clay sewer pipe collapse.

Although they have violated numerous clauses, (including the final straw of moving in a nanny who is not on the lease nor did they ask for permission) I nicely offered to mutually part ways with them.  

Throw some dummy cameras on that sucker?

I am currently putting up external cameras, have signs asking guests to respect quiet hours, have ordered a decibel monitoring device, and have visited with the police to explain I do not cater to parties.   

I once read an article about a young lady who had a house in the Boston-Edison area of Detroit, and she had so much theft that she put up surveillance cameras.

I used to bring a camera with me and take pictures of the screen shots to save time and then later enter the data into a spreadsheet. 

Do all the responsible things an STR owner should do: rental agreements, verification of renter, cameras outside, clear rules, and good insurance (among others).

I inspected every accessible part of the duct system, cleaned them several times (they were really gross) and scoped with a camera a few times but couldn't find any holes or gaps or anywhere that it could be getting sucked in or falling in. 

I use a SWANN camera system and I can look at the property on my phone.

Ban cameras?