[rwmj]

The collateral is a claim on future earnings, isn't it? In the UK, the student loans company gets back 9% of your salary post graduation and you cannot legally opt out until the loan is repaid provided you earn over a minimum threshold.

[roel_v]

You can't squeeze blood from a rock. Sure, you can say 'hey let's garnish this guy's McD wages for the next 25 years' - but the collection costs are almost as much as you can get your hands on. Just not worth it. Well, only at very high interest rates, so that the good ones make up for the bad ones.