I consider it fair play, but it is not worth the risk. If you get killed just before you exit the game, your items are in the phantom zone, and it would not be fair play to restore them since you quit the game intentionally. With experience, you can retrieve items from virtually any situation. You just need to understand the situation. If it is really bad, you shouldn't even be thinking about killing monsters. Just 1)enter the level naked, 2)immediately cast a town portal away from the stairs (or reset the portal if you are going down a town portal), 3) get away from the stairs and away from your portal before you die. Once you have a portal and stairs that are split from each other and not completely hosed, you can start to focus on grabbing an item or two before you die.
Just another thought. If you have a town portal scroll on your belt, you can actually cast a town portal next to you and run into it as fast as you could quit the game (probably faster). Just hit the number key, right click, left click. So there is really no point in quitting the game to avoid death. I guess the exception here would be if you are playing one of those thousand mana arty mages and get into stunlock, where you cannot cast a portal or move into it. But if that is the case: slip on a ring of harmony, drink a blue potion, and the enemies will fall on their knees and beg for mercy.... "Pleeeease, no hurt. No Kill. Keep alive and next time good bring to you."
Just another thought. If you have a town portal scroll on your belt, you can actually cast a town portal next to you and run into it as fast as you could quit the game (probably faster). Just hit the number key, right click, left click. So there is really no point in quitting the game to avoid death. I guess the exception here would be if you are playing one of those thousand mana arty mages and get into stunlock, where you cannot cast a portal or move into it. But if that is the case: slip on a ring of harmony, drink a blue potion, and the enemies will fall on their knees and beg for mercy.... "Pleeeease, no hurt. No Kill. Keep alive and next time good bring to you."