Playing the game out just to get the opportunity to report someone - that is essentially a guaranteed loss when you have a champ select troll - is not an option. No one wants to sit through 15 or 20 minutes of a nunu running it down mid, or a "support" that actually just went an ADC and is now competing for CS because they didn't get the role they wanted. It's a miserable experience to play with, and in ranked, that loss still counts against us. Even if we do sit through it and report them, there's no guarantee it will do anything, and even if they get punished, it doesn't actually help the person that reported them in any way; the damage is already done.
So our only option is to dodge, which means they get away with this behavior time and time again without any punishment for it.