Who can rent, a stranger, intimidate family or any other restrictions. 

Strangers will want to see you do it a few times before committing.

In addition, since I often meet strangers alone to show empty apartments, I believe this is process is important for my safety and when I show occupied apartments, for my existing tenant's safety when I take strangers through their homes

IF you think you won’t regret the thousands and thousands of guests you’ll have to deal with over the next 30 years AND you can get over the fact that thousands of strangers will be doing disgusting things in your bed.

No one trusts a stranger.

Instead of marketing to a bunch of strangers, strengthen existing relationships and then (eventually) ask them for referrals.

Housekeepers complain WAY more about family and friends than paying strangers. 

Coops don't like investors because they are a community of shareholders with common goals, and those goals don't jibe with letting strangers into the building to stay over for a few nights.  

I would suggest trying to find those emails/posts and read through them.Regarding 506(c) exemptions these what-used-to-be-stranger investors can be converted to a 506(b) relationship over a period of time.  

Are your new neighbors and the HOA going to be happy with strangers in the building.