For the record: I have NO SYMPATHY for someone who defaults on an obligation even though they have the ability to pay. I really hope they suffer the consequences, which they apparently have not really thought through. I'm done discussing this. Frankly, the attitiude of some FReepers on this subject is pretty disappointing.
Poppycock.
The commitment specifically countenances the possibility of default.
The lender sure as hell isn't going to refund the borrower the extra interest the borrower pays to cover the risk of default. Neither does the borrower have any obligation to make charitable donations to the lender or bank who owns their mortgage. In a fair contract, both parties should be able to follow their own self-interest.
If you can't pay your mortgage, the lender is entitled to foreclose on you. If your mortgage no longer makes financial sense to you, the borrower is entitled to walk away and incur the resulting penalties. Fair's fair.