Correct me if im wrong but poloniex have very strict policies about giving an account to someone, or even changing the information. Giving the account to an escrow is not enough because the lender could still be at a loss. Plus, if the account itself is collateral, why would anyone lend you 10btc and how would they get their money back in the event of default?
I'm not sure about these policies, but i can read about..
About the loss..i don't think will have any losses..because when you put more money as a collateral, you can buy more XMR for a example..and then close the position..and have the money back..
is important to be clear and directly .. my intention is to reduce the losses, I consider that it is better to pay someone to do this (10% for a minutes lend) than to lose all to poloniex ...