Concerning abandoned properties, it wouldn’t matter in a SHTF scenario where we’re not going back to the way the world used to operate, but in current times, a potentially bigger issue than liens would be environmental hazards. That liability can be much greater than the value of the property, hence why it was abandoned. My son recently looked at a 50 acre property and we saw an old car that had been pushed down a steep embankment and came to rest next to a small river. Next to the car was an old oil tank that had been similarly disposed of. If either were leaking, that property would be worthless. It is headed to foreclosure and in those cases, there isn’t much of any due diligence for the buyers.

Worthless? Not to the scrappers I know.
Things like that just vanish for scrap weight.
Most places the eco freaks haven’t taken over, that’s just the back 40.