Would you be interested in helping me secure a tower/lease?

They are more concerned about financial security and they generally have income to invest in themselves if they must to advance.

What are the barriers to the security?

There are certain techniques and strategies needed to do well in these areas, but I would only use this vehicle for a short term investment (3 to 5 years)!

If they want, they can basically pay the first month's rent & security deposit, move in, then say, "Yeah, we're never giving you a dime again.  

This is an "ad platform" model, and the one many project-driven issuers are using as it is exempt from all regulation (the offerings themselves still have to comply with SEC rules and state securities dealer laws, but the portal itself is free from oversight so long as it conducts business legally).There is a lot of internal industry debate about which is the best and there is disagreement among securities attorneys knowledgeable in the space about what is required.  

I think that ROI is way better measurement and underwriting technique. 

How do you feel about the technique of saving 100K and taking out 5 loans and letting the tenants pay your loans?

Not to me.True I am more 'invested' than one who just buys a business or paper security, but I can add value and have the satisfaction of ownership.  

Establish a security deposit5.