iPad on the bench

[BayStateRef]

Had to deal wtih the iPad on the bench the other night at a varsity girls game. Assistant coach was holding it when we went over before the game to introduce ourselves.

Thanks to all the posts on this forum, I told the head coach it could not be used. She was not happy...and made quite clear that I was the only ref to ban it this season.

Other than the "informal" opinions I have seen posted here (from NFHS and from IAABO), is there specific, formal guidance on this issue?