Instead of baracading yourself in the corner, why not take possion of the trackball and make your rounds around the track. That way you won't impede traffic and you'll earn points as well. Not a very nice strategy, but I guess you could call it defense.
Seems like its barely not against the rules to have possion of two trackballs as long as you don't hurdle one, but I will be amazed if anyone builds a robot that can keep in possion 2 40" diameter balls.
