Seems easy enough to settle. If the robot can win against human teams that sweep, then we know you don't need to sweep (to beat humans). If the robot only plays against non-sweeping humans though, we don't know.
Also, I assume the purpose of this exercise is not to improve automatic curling, but to challenge an AI/robot with things. If the purpose is the challenge, or the accomplishment, then it seems to defeat the purpose to rule out the challenging part of the competition. This is like how I am a world class basketball player, if you discount scoring, I'm the equivalent of anyone in the NBA.