You are kidding. Most keepers are 5 foot off the line as it is. If they kept one on the line itwould be an improvement
He actually kicked the ball boy. Tried to boot the ball out of his hands and clearly caught him. No rule change needed here, though. Just apply the current ones and stop the ridiculous time wasting and disruption.
That's down to the referees not applying the laws of the game. The same thing will happen even with this new rule. If the rules were stuck too, then obviously the way it is now would make it easier for the penalty taker rather than let a keeper have one foot in the air.
