Do I quit Warzones? No. I stick until the bitter end because I like to learn from my own and other players' mistakes and I have improved my tanking abilities dramatically because of it. On those ones where there's absolutely no way the team can win, I look for personal victories.....how high can I get my prot score, medals, objectives, etc.
Do quitters upset me? Not really. This is a game and players are supposed to have fun. If you aren't having fun and find yourself screaming at people in chat, you should do something else.
Should there be a debuff? Before I read this thread I would have said "no," but I really like the scale debuff idea. I've had random game crashes, automatic reboots, cats tripping over the power cords and it sucks. Especially when in a final winning match needed for the weekly.