Yes, once.
Service: STEAM
Game: Counter Strike: Source: Gungame Pro mod
I play Gungame A LOT, one day whilst on my favourite GG server of the teim I ended up playing two against one. Gungame prop requires two kills (as default) to advance a level, so every time I killed them both I went up a level, whilst they would have to kill me twice each to go up one (Gun game favours the brave outnumbered!).
As a result I was on the P-90 before either of them were past the early pistols. One starts talking to the other in Teamspeak and the other replies on Alltalk, so I only hear half of it. But it went.
"Yeah, he's gotta be,"
"Yeah, I'd do that, go for it,"
Promptly Banned Permanently.
Or so they thought, unfortunately for them, I was head admin of the server at the time. I'd even given the guy his bloody admin powers! He didn't keep those very long, I gave them both a one week ban from all servers 'for being dicks'.
There were some hilarious grovelling emails too...