No penalties? Then what's the point? Does that mean players are more or less willing to play a whole game? I'd be less willing really.. Then again, I don't know how DoTa works.
You could do the same thing in Lol, but you need a "smart" team and a chat record in case your reported. I mean, if you warn the enemy team after discussing a whole team quit, and the enemy team plays for five-ten minutes, pushing furiously and unchallenged, you think they'd stay? I mean, if they want a "WIN" on their stupid match history record, then sure... But really, if people of this community can put out some kind of "rule system" like this, then there could be the quitting with no penalty easy. also, people won't need to waste at least 20 minutes playing for no reason if you, and team, aren't trying. 4v5 isn't that unfair, depending on how well your team plays vs. theirs.
But like countless others have said, as well as I, just suck it up. You'd get bad games, even miserable games, but don't bother yourself with it. Really, don't waste your time. Watch T.V. while playing the miserable game. If you aren't in-tuned to the game, what's the point? If the majority of your team finally wants to surrender, then surrender. If not, don't act as if you're trying your hardest to win if you've really just given up hope.