He ensures his opponent has nothing to gain from defecting...

(Rules etc until 2m 30s, then the game)

http://robowar.sourceforge.net/RoboWar5/Theory/theory.html#A...

"Essentially, the idea behind the Alliance was a simple recognition that the scoring system for tournaments up to that point made no award at the time for killing one's enemy, only for surviving the battle. It mattered not even if the enemy was still alive, so long as you were alive at the conclusion. So in the Eighth Tournament, someone came up with the screwball idea that maybe they shouldn't bother even fighting at all unless they came under attack from their enemy. Either it was amazing coincidence or there was an active conspiracy of communication going on that I was unaware of to build these horrible things, because a few more of these guys showed up at once than coincidence would seem to warrant in the Eighth Tournament.

"I refer to this bunch as the Alliance because that's essentially what it is. The robots agree not to fight each other so that each gets full credit for all of their battles. When Allied Pacifist Scum are in battle with each other, both get 100% points for their battles. If they fought it out, each would get 50% if they were equally matched, and both might well get less than that, since a double kill doesn't benefit either one of them."