It does however, give me pause to think about how to prevent such attacks.

Lender licenses are state specific, so not knowing what state the subject property is located prevents a lender who can lend in that state from understanding this might be a deal for them.

Fence off the back of the property and prevent any access from alley.

In all likelihood, you will have to close twice, and there could be a deed restriction preventing you from selling or encumbering for more that 20% over what you paid for 30-90 days.

We often pull our city gutters out, fill the holes with brick/cement to prevent rats, etc. and re=rout the gutter).

Preventive measures will have to be in place at some point on the part of the hotel industry.

Is there anything else to consider, like zoning laws, that would prevent turning a triplex into 4 or 5 units?

Usually with a simple phone call will suffice, but doing it in writing will be more effective and will prevent any miscommunication.

The bigger openings definitely help to prevent the clogs more.

But one drive through the neighborhoods and you would understand.So the problem that an investor has is finding a tenant that will take care of the property after rehabbing it and preventing looters from trashing it during and after a rehab.If people aren't willing to help the neighborhoods themselves, Investors will have a hard time as well trying to bring up the neighborhoods.It will take some big team effort to bring the city back I think.