I am not talking about a security as in SEC offerings, I am talking about the note, insurance, and a good loan to value ration to secure their money.

Is there a vacant to occupant ration (how many boards vs properties being occupied) on a block I should consider?  

Anything that is pegged to fear rather rational or irrational, is unpredictable at best.

As your buying rental and your debt ration is your current Piti and what negative rental from the property your buying after calculation of thr piti & 25% for operating expense from 75% of potential income. 

That is a negative cash flow of about $400 per year.Now, this is the part where you start your rationalizations.

The fact that your doing this sound like you are making an emotional decision and not a rational one. 

After further consideration, I was pleased to remember that this is a forum for rational and responsible people, not those it-should-be-illegal-to-offend-me folks.My "crime free" lease addendum includes provisions allowing an eviction over suspicion of criminal activity, so I agree with @Chase Gochnauerthat the intent is to deal with disturbances, not provide for a penalty.  

If you are not in the right market you will lose money, rationalize the losses, and lose more money, get frustrated, and give up.  

This kind of thinking is emotionally based and does not take into account affordability, price/rent ratio, net present value or other rational factors.Per The Economist, "If you take the 24 years covered by the US data and divide them into three, then the average house price gain when real rates were high was greater (at 2.25%) than when real rates were low (1.7%)".So how does this play out in a long term negative interest rate environment?

Assumption 1:  If the tenants pay their own utilities the expense ratio should be around 30% (in a well run park)Assumption 2:  if the owner pays the utilities the expense ratio should be around 40% (in a well run park)Assumption 3:  Do math for a 10 Cap-it works for any Cap rate you choose including  positive or negative*************************************************************************************************************************Net operating income=gross income - expenses Using the expense ration of 30%  => Net Operating Income*(1-expense ratio)=> NOI*(1-.3)Therefore:NOI/yr=(#lot)*(rent per lot per month)*(12 month per year)*(1-expense ratio)Cap Rate=NOI/Purchase pricedo some 8th grade algebra followed by some 6th grade math (dividing with a decimal)Purchase price=NOI/Cap rateTherefore:Purchase price{tenants pay utility}={#lots*Monthly Rent*12*(1-.3)}/0.1 =>84* lots * rentPurchase Price {owner pays utilities}={#lots*monthy rent*12*(1-.4)}/0.1 =>72*lots*rentThere are the 72/84 numbers derivedIts not rocket surgery.