The rule was explained to me like this. If a team is using the boundary line to set up a screen, then it needs to work as such. The rule makes the boundary line part of the screen and this is the same for both offense and defense. Stepping outside the line is an attempt to circumvent the rules and gives an unfair advantage. This applies whethter the offending player receives a quick pass and two points or just a better floor position.
I had one game a few weeks ago where a team was running a play with this move consistently over and over. The player who ran out of bounds was actually running BEHIND ME!! when I was on lead. I consulted with my partner and informed the coach at half-time that this was illegal and if it happened again we would call the T. No surprise: it didn't happen again! If it had made any difference in the game such as points or obvious advantage I would have dealt with it earlier, but the way the game went it never mattered.
|