I spoke with a BK lawyer doings mods, a while back, and he said that he was doing rentals and cash flowing them depending in the circumstances. Basically, you would have to prove a “hardship” beyond just financial mismanagement, which is loosely defined.
It’s all irrelevant if further declines via deflation are in the cards and they get stuck with a recourse loan and possible loss of income. It could very well end up being a trap and do very little for maintaining price levels.
As an aside, they also did forensic mortgage audits(which the use as leverage in negotiating new terms) and found that over half of all documents had some sort of violation.