Sorry to butt in but... it may not be by default, but the GM can delete characters, right? So if you want to leave and don't want to leave your character up for grabs, you can ask the GM and they can decide if it's "appropriate" for said character to just disappear or something.
I'm also a bit divided on that feature, but I figured if I ever really really wanted my character deleted I could just nag the GM. XD