Correct - and most users walk away rather than go to court for what is (usually) a small amount.  BTCJam doesn't care - they get their cut up front.

In Canada, it's actually very easy to collect on a debt certificate.  Just simply file it in court and you get your money - the defendant has no chance to provide a defense because he/she has already lost. 

I started up a website called coindebt.ca and even then I couldn't find enough interested people to make it work.

That's why you always need collateral.