US banks are foreclosing on crappy, formerly overpriced sub-prime housing and then not taking title to it, in order to avoid the taxes. This could create suburban abandoned zones of boarded-up houses,where the local tax-base is depleted, undermining schools and services.
The local market conditions are what seems to determine the abandonment decision. In a region where the job and real estate market is doing anything better than "a little soft," I would surmise that abandonment makes no sense at all.
However, at a certain point, in a weaker region, with declining neighborhoods, certain lenders might make the decision to simply walkaway from a large swath of (potential) real estate holdings, on the simple basis that it might be cheaper to do so.