It's been false for me. If you had said, "There comes a point in several campaigns," I'd have said "true." However, it's maybe one campaign in every three or four. For the most part, we'll have character friction based on choices made, or we'll have smack-talking-fests, but not to a point where blood is drawn or spells cast.
In my 4E campaign about two months ago, it happened - the wizard loved using his Orb of Blood ("Orb of Sanguinary Repercussions", a damned stupid name) with the Cleric of the group in range every time the cleric was bloodied. It affects EVERYONE in range who is bloodied. He'd done it twice before, so the player of the cleric decided that the cleric was fed up, and cast one of his big spells (Cascade of Light, I think?) On him, and CRITTED, doing max damage.
The wizard responded by unleashing some whoop-ass on the wounded cleric, and the Shifter Ranger in the group saw the exchange, but not the initial incident that caused it, and unloaded on the cleric, killing him dead, dead, dead. The group just decided that the cleric had lost his darned mind in the depths of the dungeon, and looted his body and moved on.
It looked like there was friction between players, but they assured me there wasn't, and they were just "having fun". So the Cleric player announced he didn't want to keep playing the Cleric, he rolled up a different PC, and they found a captive in the dungeon that they knew from back in town, freed and equipped him, and there wasn't a problem after that...
Before that, the only other time the party came two blows was about five years ago, in a Forgotten Realms game, where one guy was playing his last game session before moving away, and wanted to make a "memorable exit."
