I read an article by a psychology professor, who was analyzing behaviors of people in a train compartment, when someone has a compartment for themselves at first and they spread out and then an hour later someone else joins them.

If it's the former, I would do the repair as, in my opinion, windows that have ratty or missing screens make the whole house look terrible and it's an issue if the tenants want to open a window to catch a cool breeze rather than run the air conditioner (behavior which should be encouraged, in my opinion).I think the larger question is why, when there are so many properties in the country that cash flow really well, why you're hanging on to one that does not.  

Stop this childish behavior.

The bad behavior on payment will most likely only get worse.

If the contract rewards you for certain behavior, you are going to drawn to that behavior if it benefits your business, whether or not it is best for your customer. 

But it's exactly this kind of behavior that brings the whole turnkey industry down with it, so I personally find this more than irksome on a number of levels - I can't even imagine how those who got conned feel. 

This kind of behavior is not professional and illegal.

A few years ago I saw a truck dealership (commercial trucks) that had quite a few of the smaller delivery type trucks being displayed along the road (small box on the back like a small U-Haul with a van type front end).

How is @John Thedford benefitting from his behavior and spending his time on this?

I cross reference between them to make sure it makes sense.If I see any issue I ask the applicant and if they are responsive and honest with their answers then there is more chances I will accept them then someone that is not honest with their answers or take to long to respond.I test both financial stability of the applicants and their behavior and attitude.