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.

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.

Let them both know that any behavior that is directed at another tenant that is meant to alarm, torment, terrorize - including name calling - is considered harassment under the law and would be a lease violation that could result in their eviction.  

You're best determination will be to actually see the areas and observe behaviors.

I can not believe that unprofessional and disrespectful behavior.