Why would they allow their student loans to default in such a situation instead of enrolling in an income based repayment plan? If they have 0 income, they would have a payment of 0 dollars, still get their tax refund, and have their loans forgiven after a some time on the plan.
Not all federal loans allow income-based repayment. For instance, parent PLUS loans aren't eligible, nor are other loans made to or through parents. Moreover, there are tons & tons of private loans (often with high interest rates) pushed at these places, and none of those need to offer income-based repayment.
