In the end I felt good that we stopped further violence ( at least for that day) and maybe even made the guy think a little - hard to say what ever happened to the couple or how they turned out - if they were tenants of mine, I probably still would have approached them - if nothing more than to prevent someone from a continued beating if possible. 

@Danny Gilley if you used the standard NC lease form you are covered by 17(D) where partial payment does not prevent you from evicting the tenant.

This will prevent undercutting. 

We manage several properties in the so-called war zones and these are my take-away's if you're looking at those areas:- almost all buyers (investors) are cash buyers- very few would pay $50k for the area, most would be lower- Yes there is theft and some bad tenants that we have to evict, but you can prevent a lot of that with a good management company. 

If so, is the contract enough to prevent them from getting their house back?

If the majority are owner occupied, the board could change the bylaws to prevent or reduce future rentals.

If it wasnt the dogs or the pot preventing them from paying their rent, it would be something else. 

I would then put in writing that as preventative maintenance the dryer ducts be cleaned every 6 months or whatever is suggested from a duct company based on how the vents are set up.

You ask about how to help prevent a loss in a crash.

Federal law requires landlords to provide information to tenants about the prevention and clean up of mold.... order the EPA booklet "Mold and Moisture in the Home" available by website download or as a pamphlet.