Just throwing this out there but why would you only lend 0.015BTC to a legendary member but ask for collateral? If it's their only account I doubt they would want to use an account worth 10x the loan for collateral, just saying. Also yes I agree that everyone should haven't an escrow hold the collateral as this user has virtually no reputation here.
did you think that he/she maybe can offer altcoins and virtual goods? not only forum accounts are collateral
just saying
regards.
-Katerniko1