The risk is on the lender more than the bank, after delivering the coins there isn't much of a chance of getting them back unless legally secured against a valuable asset
That is right! But the lender got a protection against such circumstances. Actually, I sometimes go to Lending section of this forum to find something interesting in there and also taking a chance to learn someting new and here's what I noticed. The lender do not easily accept applicants, they interview it first mostly asking about their means of living or how they gonna pay their debt. Then if both parties agree, the applicant should give a collateral before closong the deal. The purpose of it is to let the lender at least get something valuable if the applicant suddenly btoke their deal. Collaterals could be in a form of crypto or crypto, bitcointalk account is not accepted.