4. Try to understand how important the account. Few member id is precious to them than few legendary. Earlier who has written anything even gave bounty report became legendary so their account is not important to them and also they have multiple account. So, if you give 500$ loan that might be defaulted.
No, they should just stop taking accounts as collateral if they don't know the lender personally. You can never truly know who's the real person behind the account. Take Atriz == Zapo or pinkman12345 == ChevasRegal for instance. Don't let the rank and green trust of the account blind you.
If lenders view lending as a business, then surely there is a risk model they use, however basic and erratic it may be when it comes to this section. I would even go as far as to say that knowing the lender personally increases confidence, but not the likelihood of repayment. Past performance in terms of trust is no guarantee of future performance, only past performance in repayment - that's how the lending industry works.
But as pointed out above, don't use metrics that benefit scammers - scammers rely on the hope that lenders make this mistake. Do what the successful ones do and simply don't accept accounts as collateral.