[robocup-small] the rule of "Two defender in defence area"

[yonghai wu]

Hi everybody,

     Maybe everybody in Mexico has a very deep impression on the law
of "Two defender in  defence area". There were 3 penalties in the
Quarterfinals Skuba vs Immortals due to this law.
    Law 12 of  rule 2012 give the detial definition: is the second
defending robot to simultaneously occupy the team's defence area in
such a way tosubstantially affect game play.  But the rule did not
give a clear definition of "substantially affect game play", is all up
to the referee. So the problem is comming, i remembered that maybe
more than 50% argument during the game are related to this law.
      In real soccer game, there has not limitaion of the number of
defenders in defence area, but only allow the Goal keeper can handle
the ball, if the other player touch the ball with hand, he will
receive a read card and the team will receive a penalty.
      We can learn from this real soccer rule. All the robot can enter
it's own defence area, but only the goal keeper can touch the ball, if
the other robot touch the ball, the team will receive a read card and
a penalty.

         Best regards.

                                               Yonghai Wu