Somebody wanting to sue for you backing out of a bad deal or accusing you of selling them a property with defects like unknown termite damage).

@Julius HallIve personally had good experiences with them, but can give you more info in a DM if you want, lest I be accused of any shilling or untoward behavior

@Jamar LockwoodIve personally had good experiences with them, but can give you more info in a DM if you want, lest I be accused of any shilling or untoward behavior

You are probably in the right and are not required to take action but there might be an accusation down the road (if a break-in etc occurs) that the situation was "foreseeable."   

You could be opening yourself up to slumlord accusations.

He followed up with text messages threatening to take me to court for trespassing, accusing me of charging military too much deposit (not yet a law when he signed the lease), and how dare I put a lock on my gate. 

It's easy money for them and let's be honest, who is going to have sympathy for a landlord accused of violating fair housing laws. 

Think about liability: what if your tenant accused you of breaching the lease and that you stole from them?

I know you don't /have/ to have an LLC, its just for liability protection, but since we have the business entity, not sure if we should use its separate bank account to more clearly keep business money separate from our own personal finances so the IRS doesn't accuse us of commingling funds?

The woman on the second floor flipped out on them accusing them of being nosy and controlling.