There is a line between defense and agression (as mostly seen from my team's robot 469). For instance: robot A places its arm above robot B's open hopper.
Defensive: rbt-A holds its arm above rbt-B and trys to block balls from falling in.
Agressive: rbt-A bashes its arm continuously into rbt-B's hopper, hopping to damage some system and cause damage.
Most of the current judging is based on how "intentional" an action is. If you look at some of the matches, you will see shoving matches, robots falling over everywhere, etc. The referees had a difficult job this year, especially with all the arms and large box robots that could be prone to tipping. Personally, if FIRST were to remove all defensive maneuvers from all games, then there would be much less variation to the game, and to me, it would be boring to watch
>>"hey joe! look! rbt-C is going to cap the large goal and gain 40 points! shouldn't rbt-D go and block them?"
>>"they can't touch any other robot on the field, so they can't do anything about it."
As for the entanglement issue (
see this controversial match), it is not clearly defined. ANY fabric on a robot is prone to entanglement with other teams, so how can this be sorted out? should teams not be allowed to go anywere near fabric-teams because they could get caught? Most teams do not wish to be intentionally stuck on another robot, and unless the action looks clearly intentional the judgement is left to the refs (thus making their jobs more difficult)
overall I believe the current rules are fine for the purposes of defense, but it is difficult to definfe how intentional an action is.
_Alex