As account trading is not trustworthy taking account as collateral means 0 collateral and if default then from there lender can get 0 satoshi. But by taking account as collateral may decrease more scam activity as Borrower will not have any access of the account. But if the lender is the same of borrower I mean if lender trades the account then his personal account as well as selling account should be tagged negatively. As happened for grtthegreat