Keep in mind that there are a limited amount of balls available, and once your robot loses control of that ball, whether by scoring, defending, or just playing around, then it is free to be picked up by anybody. Assuming you shoot it far away, you've got a 3-2 disadvantage at retrieving your alliance's own ball. Better to use it judiciously in gaining points than to momentarily distract one member of the opposing team.
Another interesting thought: if your robot is the backbot and it's wide enough, you could use it to block the view of an opposing driver; just be sure you get off the platform before the end of the match. Better door than window, right?
Gracious professionalism could be argued, but I see this defense as analogous to guarding the in-bounds pass on the basketball court. And you can't get much more graciously professional than the NBA, right?
