Fanaelialae
Legend
IME, this does not lead to more fun at the table (assuming the player is just jumping the character off for the lulz).What you have described is a disruptive player. Whether because he's deliberately being disruptive or because his idea of "fun" is completely at odds with the rest of the group.
This is not an in game problem and should not be treated as one.
But why do I care if the player is "treating his character like a token." As long as he's staying within the rules, not being disruptive, and not subtracting from the fun of the table, he should be able to play his character how he likes.
As DM, I have most of the control of the game - especially in D&D - where player narrative control is extremely limited.
I try to not but in on the players controlling their character, and assume, unless shown otherwise that the player is doing so in good faith. So if the player has his PC dive off a cliff I don't assume anything but that they're doing it for the fun of the game (and willing to take the consequences of doing so - which may very well result in death or other negative).
It wrecks the fun of everyone who is trying to take the game seriously, because it destroys immersion and wrecks verisimilitude.