IMO lemming trains usually don't happen because morons didn't do the right thing, they happen because of normal distribution of player deployments at the start of the game.
Usually most maps have a corridors, one of them a heavy tank corridor, the other a medium corridor, and maybe a middle that players stay out of with maybe TDs camping from back. When the game starts most players just deploy where they like to go on that map, with a few sitting back seeing where everyone else is going. This is all very much influenced by the rng of player make up.
You may wind up with heavies that prefer to push with the mediums, meds that run with the heavies, or TDs that don't sit back but push with one group or the other. More timid players may hang back. Based on rng and normal distribution, every once in a while one side MUST overload, leaving the other side undermanned. The sit and wait at the start players may see that and nope out of the undermanned side.
Sometimes players in speedier vehicles may flex back, and re-balance the distribution, but slower vehicles are mostly stuck with their decisions.
Point is that just as rng determines the skill of players making up both teams, where players deploy on the map sometimes resulting in lemming trains is just as much a result of that rng. Yelling at your teammates that no one went X line – when YOU didn't either – makes no sense.
Instead deal with it, either pushing that train or flexing back to a position where you can defend the weak flank. If you find yourself alone on a flank, retreat sooner rather than later, something I need to do a lot faster. Too many players go to the usual spots on a weak flank by themselves, only to cry and curse their teammates as they're overwhelmed.
Would be nice to see some stats around it, but I doubt lemming trains lose more or less than more balanced map deployments. I do hate players blaming their crappy team for a loss, when most players are part of the blame, and it's all rng anyway. Do the right thing, play well, and over the long run things will balance out and the results will reward your efforts.
