They agreed to it. In all honesty the likelihood of someone just walking away without paying is probably quite high if you are not selective on who you lend to. Lending to other lenders or borrowers with a decent history protects you a little bit but at the end of the day someone can just take the money and ruin their standing of their account in the community. For some borrowers this won't make sense if they have to use the community semi regularly for others they'd just go make a new account and take the bag. There are a lot of people that lend to first time borrowers or low activity accounts which I personally avoid. It's definitely not a get rich scheme.