[RRLedford]

There is a rule (forgot the number) disallowing actions by a robot that interrupt the flow of the game. So, covering all three open faces of the goal could only be done intermittently, like while the ball is arriving.

If your blocking device leaves too little room for the ball to enter goal, and it is maintained in that blocking position while a robot is trying to insert the ball into the goal, then you would likely get penalized.

-Dick Ledford