Disallow Teams Entirely
Going to post this as its my opinion on the matter. The whole idea was actually my fault, too. It was a loophole in the original rules that wasn't explicitly mentioned but which skirted the boundaries of what was listed. I voiced the idea in chat with the expectation that it would be a cute attempt, but get blocked for violating the spirit of the challenge. SuperStormer just happened to actually write up a pair of submissions before I'd move on from just thinking about it to actually writing code.
I did this with Adventures in the Ruins too, and while it was deemed illegal, it also wasn't a long term winner due to the structure of the challenge: as only 8 bots would be run at a time, winning bots would play again and losing bots would be eliminated, until only 8 remained and those would then play for the final score. As one of the team literally sacrificed itself for the other, it would not move on to the next round. It was silly but a fun out-of-the-box bot.
Most of the suggested rules on how to limit teams has been very subjective or otherwise near unenforceable (e.g. "the owner of the team has to give you permission to identify as the team": this means that if the team is posted performing a given set of moves to identify team members, no other bot can ever perform those same moves which is silly).
Several other factors come into play as well, regarding what methods a solo bot can perform to defend itself against a coordinated attack from a team of bots, and as things currently stand, there is nothing a solo bot can do that's allowed. Or how is a team scored with regards to its placement in the challenge? Does the
worth of the highest single bot counted? Is it the average among all team members? How does the controller know what's a team and what isn't without alterations to the controller that doesn't render it a unique challenge?
I have nothing against team-based challenges, but this one wasn't meant to be one and it should stay that way.