Yeah, I'm starting to see more mid-game quits, which is a bit poor as being down one man is a real team cripple (on the assumption that they weren't just feeding prior to quitting).
Unfortunately, we've been seeing these in WEE too. People throwing a wobbly because they're losing and quitting (therefore making them true losers) seems to be fairly common.
I blame overly competitive assholes. If the game isn't fun if you aren't winning, then either the game isn't fun and needs a redesign, or you need to take a long look in the mirror at yourself and check your priorities.