[@Whimsley] While they might not be allowed to RESPOND to the choice of the other trainer, I do feel that the winner should be allowed to bring their exhausted Pokémon out of battle in exchange for a clean slate. I personally feel the "best out of X" method would work much better in a real-life setting than a "we fight until one whole team has been defeated". What would you otherwise tell the first Pokémon you send out? If you can't take that one out of the fight, then you're essentially dooming it to be beaten up before the end of the fight as the enemy will just send something that can more easily fight it. XD

But yes, "Matt is about to use Poliwhirl, would you like to switch" clearly doesn't work. So, allow to take back, but both next Pokémon must be revealed at once, so none is responding to the other unless the winner is like "My Kakuna can beat anything you send out!". That's my suggestion.

And in case of battles against criminals without rules... They would be rule-less, wouldn't they? Hahaha...