If you have money in another form doesnt mean that you want to sell this. For example a steam account. You might want to keep it. Though you still can give it as collateral to an escrow.
And why should someone accept 50% risk? The scammer could have planned to scam an amount 50% of the taken loan. Then you gave him 100% of what he wanted that way.
It's not just about scams, its also about accidental defaults. There could be cases where the loaner just simply cant pay the loan back and it defaults on it.
For example if you give out 0.5
BTC for a gambler and he lose it all, but his income is from faucets only and he cannot pay it back at all.
In that case you need to factor that in, every bank or loaning agency does the same, there is mathematical part you cannot ignore when working with money , merely probability & statistics
If many scammers appear suddenly then you got 2 options:
raise the interest rates to cover the losses, or implement stricter rules for giving out loans....Or just take collateral to make sure you're covered. Forum accounts are the best thing imo. Raising interest rates isn't really going to do much because any higher just makes it even less worth it for the borrower and less likely they'll pay back and even if you did raise them considerably it's still not going to be enough to cover losses. All you need is one scammer to not pay back and it will put you in the red from all your over loans.
First of all you raise the interest rates on all clients, until the funds are recovered.
Also give out equal loans, giving out random amounts wont help you quantify the risk, but if you give packages of 0.1
BTC and their multipliers then it's easier to quantify the risk.
Depends of course of your budget.
If i were to loan out 1
BTC i would split it up into 0.02
BTC packages, and only give out more than 1 package to 1 person if he has a good reputation.
Otherwise a no collateral loan would also work, but of course only after some background check (account standing, previous things done, other loans, forum post quality / projects, etc)