Also, I would possibly contact the police and see what their view is.

It doesn’t matter if there is zero intent to discriminate in carrying out such polices.

The police show up and arrest the daughters for trespassing.

@Michael Biggs My understanding is if you have an Airbnb guest that overstays their welcome after staying a week, you can have the police remove them for tresspassing since there was no expectation of residency with your agreement through airbnb.

The police were called and a police report is being filed. 

Finally, most of the local police/sheriff's deputies have no problem coming to "stand by" if you explain a potentially bad situation...of course, they are dependent on call volume and might not work on your schedule...and you have to have some idea the tenant isn't reliable or you might never think to call.What else? 

And then, Baby-Daddy moves in and the couple have knock down, drag out, screaming, violent fights, with the police showing up and multiple other tenants complainingSo, did the co-signer make sure the rent was paid on time?  

I am not a judge, a police officer, or a dog-catcher.

That could include a perimeter fence, security, getting a police officer to live there in exchange for discount or free rent - increase the deposit on the move-in to make people really want to get it back when they move out 

Maintenance is deferred and most owners turned their units into rentals, hired property managers who did not care for tenant quality, which resulted in 10 people living in a unit, police coming over, drugs, etc and all the good people leaving.