Death is always on the table for my characters, and--so far--it's only happened once. However, another player used their character to bring mine back from the dead? I wasn't totally okay with it, and I even had other characters in the RP, but I went along with it. Looking back, I wish I hadn't--it kinda ruined the immersion for me. 

So personally, I try to avoid players and RPs that restrict death. Even "ask to make sure it's okay to kill someone's character" is a little too much for me. If your character is in a position in which he should die, he should die. Plain and simple. And it's not fair to the other players who might have to play OOC to avoid killing your character when you don't want him to die. I'm not saying a bloodthirsty character should necessarily be allowed in every game or anything, but if you poke a bear with a stick...