If it's during the game, and the officials say they saw the play and it was not illegal, I wouldn't aggrevate the situation by asking for a rules reference - it's bound to be interpreted the wrong way, especially in the middle of a game.
Look up the rule yourself, seek to understand it, and discuss it with someone, maybe one of your referee friends (if you have any
) or someone from the local officials association.
Possibly, and I stress POSSIBLY, you could bring it up with the officials after a game (as long as you have not had any significant clashes with them) - AFTER you have sincerely shaken their hands and thanked them for their efforts. Then, taking special care not to appear confrontational, and NOT bringing up ANY specific play from the game, you could inquire about screening in general.
If you take special care to ensure the tone is friendly and non-threatening, any official worth their salt will accommodate you.
I would not recommend bringing up anything before the game - I find that, generally, nothing good ever comes from it. On either end.
[Edited by canuckrefguy on Jan 3rd, 2005 at 06:32 PM]