Investors who own single-family residential investments in these markets are encouraged to diversify their investments into nonresidential properties, or residential properties in markets that are not so vulnerable to large losses.

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.

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.

Iron work that is not locked down is always vulnerable to these thieves.

The possibility of a leak, however, gets into installer qualifications and methods which I think as investors we do have degree of control over.My opinion on the permit question is to use business considerations to gauge risk of going whatever direction one goes, and to do your best to make sure you have a qualified installer.My post was made following the post by the OP @Bienes Raices where it was stated the hot water heater in question was electric, implying that it was not vulnerable to explosion of the sort that a gas leak would produce.