What do you constitute as "guest status" and how do you enforce this at your rental properties?

Not to be cynical but it also depends on the relationship with law enforcement you have and local politics.

You need to have a good rental agreement in place and you need to enforce it.

Not a CPA, but a department within the City making and enforcing Policy

How do you enforce rules if someone make damages or doesn't leave on it etc.

I haven't been able to get a Fannie Mae or Freddie loan for 1-4 unit properties for a number of years as I am over the 10 property maximum (which they only began to enforce after the recession in 2009).I haven't before heard of the Fannie/Freddie Small Balance Loan program. 

I'm not by any means a lawyer or a housing law expert, but I found this:The Fair Housing Act (Title VIII of the Civil Rights Act of 1968) introduced meaningful federal enforcement mechanisms.

A little concerned about the enforceability of it. 

There are regulations within the city limits but they don't seem to be enforced, plus I'm just outside of the city limits anyway. 

However, you can count on being dragged into court by virtue of the fact that as a landlord you are presumed to have deep pockets...So, you need to cover your assets with proper insurance, reasonable rules and consistent enforcement.