I had a couple mishaps.
Once I sent out two requests on the same day but mixed up the cards. It was a couple hockey guys, Wayne Van Dorp and Len Esau. They were both nice about it.. Esau sent me back a note saying "you sent me Van Dorp cards by mistake, if you send me the right ones I'll gladly sign"... Van Dorp said pretty much the same thing... I sent them back the correct cards and apologized and they both signed and everything turned out ok.
another time I sent to Stan Weir (another hockey guy).... but on the envelope I addressed it to MIKE WEIR... I have no idea why! I musta had golf on the brain that day. He signed for me but included the original envelope in the return, circled the name "Mike Weir" and wrote beside it "I think you mean Stan". I felt like a goof! lol