It is not your fault! Who could ever realize that a member would default a $100 loan. Next time do check their activities for a at least a year before agreeing to any loan request. If they are active every day then the chances of them defaulting would be less. This is not a fixed solution but it will give you reassurance. I hope this low life comes back and repays the amount he owns you.
In this forum we have seen Legendary rank users also defaulted with little funds which was very unexpected. Because if those users were active in the forum, they could have paid those loans by participating in the signature campaign. So think about how many things lenders have to think about, even if they consider lending to a user, there is no guarantee that he will not default. So lenders should always be aware of this risk, lenders have experience after seeing the activities of many users in the past.