It's just a matter of time of course, but when I say that I do believe we're getting close to a recession and I do agree that little has been done to really cure the economy's vulnerability outside of housing. 

The supreme court also agreed with the homeowner, setting the precedent that "at risk of loss due to nonpayment of taxes" has the plain dictionary meaning of "vulnerable to loss due to nonpayment of taxes", and has to be decided on a case by case basis, taking into consideration the homeowners resources.

You'll find plenty of horror stories online about homes that went up in flames due to the insulation company not doing due diligence in creating barriers around HPDs. 

One side of me says "seller beware" but the other side of me believes vulnerable people should have some protections.

I guess seller financing leaves me vulnerable to Dodd Frank rules where I would eventually need to find an RMLO?  

Rekey for new master you don't need new locks,.. check what a locksmith would charge and determine if his service call to rekey on site is better than getting 8 locks mastered.. do a couple extra so you have some to switch around on turns.. same reason as he wouldn't give his master key out ,, is why you should remaster yours.Master key systems are vulnerable so limit the people you trust to give a key out to.In large complexes I was at the utility rooms, were set to a different master than the apartments.  

They are in a vulnerable position.

I have only recently learned that owning my properties free and clear puts me in a more vulnerable position for liability and know now that I need legal asset protection.

You don't need to put yourself in the middle of a drama and you calling the police could further inflame the situation and put your asset at risk. 

As others have said, it is really risky since they can cancel the policy yet squat in your property, making you vulnerable to a suit.