[KaiLan]

Here's a way to describe team stacking;
Player joins winning team
People rage quit on losing team
14 vs 16 is not good, an auto balance warning comes up
Somebody on the losing team gets a lucky shot on player
Player is auto'd to the losing team
Player quits and reconnects
Player sits in spectator until he can rejoin winning team

There, that's stacking. Circumventing the auto balance.