I am in the middle of a very busy period right now trying to buy 8 houses as well as having 6 visitors coming from Norway for a week, but i should have lots more time on my hands around the 20th of feb and after.

If it comes in low relative to contract purchase price, we make a stink about it, send a copy of it to the seller's side, scream about the appraised value from the rooftops, and try to renegotiate price. 

Many people here start screaming "CAPEX!"

I don't know about you, but for me personally, it screams I like looking for homeowners who are financially uneducated about the value of their home so I can take advantage of them.

But in the real world we need evidence, which is hard to come by regarding drugs and unauthorized visitors.  

Pocket listings, last screaming deal we got, we knew about it 3 days before it hit the market. 2.

Whenever we get a police report (and we get a lot) we let the tenants know that we know and that it cannot continue.If your lease doesn't address criminal activity, or not strong enough, I'd probably write a letter or cease notice listing the specific behaviors you want them to stop (police reports, visitors disturbing the peace after hours, etc.) to let them know you are watching more closely.  

You will need offer something worthwhile to get visitors to register. 

This just screams RED FLAG, STAY CLEAR. 

I've done a couple of these now but since the property isn't being marketed through the company, the first one only had 2 visitors and the second had 1 person -- another realtor.