The timer for this battle has expired

Not necessarily bad. Not being able to press the button because of a crash or getting distracted because someone calls you or anything else like that, I can understand. But what other reason would you have for not pressing either button. It's essentially a replacement for airplane mode. Think of what often happens in GAC, and especially in TWs. You go in thinking you can win, but you fail to kill even one member of the enemy team. Without airplane mode or the forfeit button, the battle is automatically submitted, meaning that they have unspecified amounts of pre-loaded TM and unspecified cooldowns (without the "starts on cooldown" clause), making it significantly harder for the next battle/player.