That happened to me years ago. I was informed (after the fact and just before the statement arrived) that a friend's wife had charged something to my credit card. I called up the reg and asked "WTF?". He referred me to the FBO. I told the FBO "Within 24 hours from now, one of three things will...
My attitude towards loans to friends is that I consider it a gift. If the person is somebody I don't feel close enough to make that big a gift to, then he doesn't get money.
For Scns asking for loans years ago, I would just tell them "If the bank doesn't consider you a good enough credit risk...