I think I have you all beat. In TXGenWeb, we have a weekly chat and Rob recently asked me what I was requesting money for. I told him it was the quarterly payment for the county server that we keep. He told me that he knew about that one but needed to know what the $1150 was for. I thought he was kidding (he's funny like that) but it turns out he wasn't.
Rob and I had been discussing sticker (like kids and musicians use) advertising for the TXGenWeb. Someone had emailed him using an informal tone and my signature (not my email address) and told him to send $1150 for vendor reimbursement to a PayPal account. An email conversation ensued and a followup email noted a different PayPal account. He CC'd everything to my assistant and even she didn't catch on that it wasn't me. If he hadn't asked me about it in chat, things might have gone south. We notified PayPal of the scam.
In Rob's defense, I have a LOT of email addresses but I had the most horrible fear that they would never have believed me if we hadn't caught on.
Make sure you know with whom you're "talking" by CCing a known email address for your friends and associates. :)
State Coordinator, TXGenWeb