2 groups of 23 people are queuing, waiting for one tank. Tank pops, instance is reserved, everyone accepts, tank drops. In the meantime a second tank queues, joins the second alliance, they go in, leapfrogging the first alliance.
Except they don't.
You're wrong. You refuse to see it because you don't want to see yourself as someone who jerks others around, but that's exactly what you're doing. Not only does it increase the chance that people will have to wait longer, it affects what they can do while they are waiting and not only that, it's just plain annoying to have it pop every 30 seconds and drop anywhere between 5-40 seconds later.