There is a sort of way to spot quitters.
People with lots of games, but few results (ie.e wins/losees)m especially if they have no/few loses are often quitters. This isn't true 100%, but can be seen as a sort of rule of thumb.
e.g. 156 games (30 Wins, 2 losees) = possible quitter
234 games (123 wins, 27 loses) = non-quitter (or very good player that only quits if losing, which isn't often...)
Well... you forgot that you neither get a win or a loss from a mini-dump.
Also you won't get credit when the hosts drops for any reason.
So, I think it is not wise to judge people of their scores right now, since it happens quite often.
I just checked my account and I have 60% of my games which didn't count (neither win or loss). And i am not a quitter. At least I hit surrender when game is over.