If so try to enforce that.

This is the code that most communities use to enforce certifications of rentals. 

(And, no, I'm not saying you can get around the due on sale clause if they choose to enforce...I've just haven't heard of it happening if you show that the LLC is a single member LLC in the investor's name.)

Many areas have laws that aren't enforced at all... but then others come down hard on those who break themI'd recommend making your renovation decision based on ARV instead of the ability to STR it, and then make the decision to STR it or sell it weighing the potential upside vs risks.

The airbnb site requires the registration number in Chicago.Am I interpreting this wrong, has Chicago not started enforcement, or is this a gray area? 

If they are VERY professional, they will have their processes in writing as verification that policies are enforced equally and fairly by their entire staff.6.

I have seen many people tell folks you have a contract now go ahead and enforce it. 

Of course, if interest rates rose dramatically, lenders may start enforcing the "due on sale" clauses again.

I've only run into estoppels when a lender asked for non-apartment commercial property.You should have an addendum address assignment/assumption of leases in your contract so buyer can enforce what the seller agreed to.

If they are VERY professional, they will have their processes in writing as verification that policies are enforced equally and fairly by their entire staff.6.