Except in the subprime debacle, millions of people could declare bankruptcy and walk away. With student loans. The debtors are simply screwed with no recourse. That’s a big difference.
Silly question: is there any legal way to default on a student loan? Can that be exploited? En mass? Perhaps?
Apparently the people that started http://rollingjubilee.org/ were originally working on a student debt strike project. Not sure exactly why they switched to a medical debt project, but it's certainly a worthy one.