It seems to me that the ABC allows brackets, because "you're betting on yourself", which is not considered gambling, so they say.
If that's the case, then pot games/action isn't considered gambling either. That means that junior bowlers can bowl pot games with their friends, without having to worry they'll be kicked out of junior leagues.
Now I'm not saying that all kids should go out and start pot bowling each other, losing all their money. But, what do you think..? =:^D