Been playing a bunch of PvP recently for the dailies. I’ve noticed that any time the teams are stacked against me (for instance, I’m on red, with 2 players. Blue has 4), a popup comes up saying “Team is Too Big!” and it gives me the option to volunteer. To switch to the other team. The one that’s stacked, which is why the popup comes up.
Now, it doesn’t actually switch me if I get “picked”. What happens is that it treats me as if I’m on the other team for win/loss purposes (so in the example, if blue were to continue steamrolling, I’d get a win for it, not a loss like I should), but I’m still on the correct team, and contribute points and kill stats to the correct team. I’ve had it happen where I’ve gotten rank points equal to what I would have gotten for a win, as well as earning my daily for a win. Despite not actually winning.