If it is common that a troll tank and a legitmate tank queue up at the same time, then that implies legitmate tanks show up as frequently as troll tanks. Therefore, the queue ought to move at a rate roughly equal to the frequency troll tanks show up.

It should be readily obvious that it takes considerably longer than the frequency you run into troll tanks to get the queue to pop. Therefore, it cannot be the case that the event of a legitmate tank and a troll tank queueing at the same time is very common. At any rate, it doesn't matter because you're just as likely to benefit for being in the #2 position (troll tank gets #1, legitmate tank gets #2) as you're to be harmed by being in the #1 position (situation reversed).

But seriously, just look at how long it takes you to get queue to pop as a nontank. You really think there are all these tanks out there that are constantly queueing and there's just some trick that's preventing you from seeing them? If they existed, you wouldn't be waiting for so long in the first place.