I have little experience with trolls, but the concept behind it makes no sense. "Oh god, we are gonna lose because I didn't get ADC, so now I have to surrender the game before it starts." Hopefully my luck continues and I rarely ever see trolls.
Now toxic players, on the other hand, tend to be EVERYWHERE. I get around 2-3 reports on enemies/teammates per every ranked game I play, just because you make a mistake. I once laned against a Graves/Leona bot as Ezreal/Soraka, and they made the stupidest plays ever and I got really fed. It was sad, too, as Graves was a total nub and whined about Leona in all chat the entire game, and proceeded to call his team terrible instead of actually playing the game.
Well, my friend once got paired with a guy who got pissed he didn't get mid and picked Kassadin with Clairvoyence and Revive. His team said that they didn't care and would report him afterwards, and he himself dodged the game.
I think you should just stick with the game if someone trolls and report them afterwards. I guess since you can't report until after the game so that a fair judgement can be made, dodging has a penalty. This discourages players from dodging in order to suck up the loss and report that troll. So I say don't dodge if there is a troll on your team, just play and report.