Back in the late seventies I had a character who made it to sixth level, a wizard. I wanted to continue playing him in other games but never got the chance. Eventually, computer games gave him a second lease of life, when I was able to input him into SSI's old 'gold box' engine and run him through a couple of adventures. He died (for the first and final time) when he was eleventh level. I don't recall how.
I came across other players transferring characters to new campaigns, not specifically written for their characters. Never had a problem with it. DM's call, I thought, envying my peers' opportunities.
I never had someone bring me a previously played character until last year. It was hilarious. I was looking to DM as much 3e as I could. I had a friend who'd played a lot of computer RPGs and some D&D, back in second edition. He was interested in helping me get a game together. He mentioned this friend of his to me, someone he thought I might be interested in having in one of my games. I said I'd be happy to meet him.
I went around to the guy's flat a couple of weeks later. He bragged, from the outset and non-stop. I listened. He was, in his eyes, a roleplayer. As it happened, he had never played a non-CRPG. Okay. Fair enough. He's about to have his eyes opened but it's not an issue.
Then he tells me about his character, the character, the one, the only Adjudicator Tempest!
"Woah! Stop!" Said I. "You can't play him."
"Why not? I always play him," came the confused reply.
I kept a straight face. "Okay, in my games, either everyone has a silly name - and that goes for the NPCs, too - and we play it for laughs or no one has a silly name, and we play it straight. That still usually leaves plenty of room for laughs."
"Believe me, this character is ser - "
"Okay, look. No one, I repeat, no one in one of my campaigns would be called Mr or Mrs Tempest and, even if they were, they would not, under any circumstances, name their child, 'Adjudicator'. I'm sorry. That's the way it is."
He didn't want to play after that, thank God.