Another wrinkle is that I reside faaaar abroad so I am not in a position to be an onsite arbiter of this matter even if certain members of the forum would conclude that I am responsible to solve the problems between my tenant and her neighbors despite the existence of specific City authorities who handle these problems professionally, safely and impartially, for a living.

Now, after you've refused to rent to someone, and they wind up homeless, they land on the city's doorstep, and the city listens to their sob story, decides you are wrong, and suddenly you have tax audits, building inspectors, and enough alphabet soup to DROWN you in your life. 

My first thoughts are an internal audit of the books to see who else is getting a free ride!

It could be that they were audited by the jurisdiction, had to pay the jurisdiction taxes owed and penalties, and from a business perspective, they are trying to pass that ongoing tax onto their customers.  

I bet the IRS would love to audit someone like that.. :)

Contractors could have individual codes too so you have an audit of who opened the door and when.

As real estate investors (and landlords), we have an obligation to be fair and impartial and respect the individuals and families we interact with.  

For instance, if a property goes empty and you were expecting rents during that time - leave it empty for a couple of months - nothing forces you to keep it rented.And here's the other thing, if you get audited, you are the unlucky 0.3%, and if a red flag is raised during the audit, you will get audited again and again.

Go to their office with a note pad and a phone to take pictures.Do your lease audit and financial statement audit while on site.

I represent people in front of the IRS in audits.