But education, formal or not, often requires both physical and human interactions.

It's not rocket surgery to pay attention to demographic trends, economic signals, and basic human behavior to figure out what areas are a safer bet for investing. 

Move into one unit and arm the property with security to keep out drug dealers, homeless, teens looking for a place to party, and gangs.

When tenants complain, appreciate it and listen very carefully to what they say-- multiple tenants complaining about excess traffic means you have a drug dealer and you'll need to get them out asap before you have a shooting in your building.

Doing so is considered "brokering a security" and requires one to be a broker/dealer registered with the SEC.The exception of course is if you actually are a GP, meaning you participate meaningfully in the partnership in terms of vetting the deals, doing due diligence, helping with managing the asset.

Do remember it is in set it and forget - you must review it at minimum once per week.Once we got to over 75 units UM we went with the addition of a (human) revenue manager. 

Don't overdo it, but be a human, imagine what you have liked from hosts in past places that you've stayed.Additionally, one of the MOST important things is your cleaning partner.

Humans...they'll get around everything you try to do unless you slap them right away.

Could the IRS at some level of activity (2/yr, 5/yr, 10/yr) step in and say we are actually flipping the houses and declare us dealers and be subject to short term gains and FICA?

The worst areas I've seen are probably the homeless encampments along the bike path between RiNo and North Washington/Commerce City, but it's just gross due to the combination of industrial waste and human waste, not really dangerous in the drive by shooting sense.