Yes, but it was kind of a 'perfect storm' situation.
About halfway through the first session of a GURPS Supers campaign, one of my players comes to me and says that he thinks a different player has cheated by changing his point values after I looked at (and approved) his character sheet. The player that he has tattled on does have a history of being a cheat, so a little while later I ask if I can look at his character sheet again on the pretense that I need to make a note of something (he has no idea that the other player has ratted him out at this time). And, sure enough, dude has almost doubled the point value of his character since I approved it.
I have no idea how he thought he was going to hide that kind of blatant cheating, but he was apparently convinced that he could. Well, anyhow, I call him out and say something to the effect of "Hey, man, we agreed on 300 point characters. You have almost 600 points worth of character here. Fix it or GTFO." At this point, the dude absolutely flips out and starts screaming at the player next to him (the guy who finked on him). I'm a pretty big dude and, at that time in my life, was pretty muscular. So I get in the cheater's face and tell him that he better pack his stuff and get out of my house, or I'll pack it for him - right into a rear-facing orifice.
Well, the cheater leaves, but the game session is pretty much done and over. The next week, everybody except the cheater - and one other player - shows up. Turns out that this one other player who doesn't show later calls me and says that he didn't approve of how I dealt with the cheater, so he wasn't coming back to game with us anymore.