For example on Lake ville if you win the city its almost impossible to push because of TDs, and if you win the alley you can't push around the corner in the base. You'll have to win both, which is not always possible. And on pretty much all other maps is the same. You win the flank and if you push TDs will light you up. I've seen this a milion times while playing both as the TD and as any other tank.
Edit: seems like if you win one flank chances are you're losing the other. So the tanks that are on the winning side mush return back to base and go to the losing flank (unless the enemies somehow pushed, then you stay at base). If your team doesn't to this then they get shredded to peaces by TDs camping at base and you lose the game. On almost every map. Your only chance is to win both and push both flanks at the same time so their TDs don't have time to kill all of you.
