I had one (Person A) who disconnected, then reconnected under the a different name (Person A1), but same ID, trying to convince me to make his other self (Person A) an admin. I just said I had no idea who he was talking about. He quit and soon rejoined as Person A asking if Person A1 had visited me and told me he would be a good admin. I said no, though he was sure I was gonna say yes.
Then he proceeded to repeat the process, however not disconnecting and namechanging, feigning Multiple Personality Disorder... Every time he'd change personality, I pretended I had just met him...