Nope, they're stuck there.
Even worse: when the Koalas lose a bet, all tokens in the All In stack are removed from the game permanently
So it's very much an all in, you permanently lose a token and hope that the action and the points make up for it
That makes sense. We tried it and found this faction very fun! Our only gripe was about Double Down...it felt very powerful for your opponent to get double the points. We found that most of the time when attacking a bet, the opponent would automatically go double down for the extra points, even if they thought they would lose the bet. However, getting double points AS the Koalas, and getting double cards as the attacker, was quite fun.