One team kicks off and the ball goes into the opponents' end zone and is lying on the ground about 2 yards deep in the end zone. The receiving team makes no effort to play the ball and one of the receiving players waves his arm over his head (like a touchback signal) to the nearby official who blows the ball dead (and later gives the ball to the receiving team on the 20). Meanwhile, the kicking team has run down to the end zone, falls on the ball, and claims that it should be a touchdown as the ball is live and in play. (We can argue about when the ball was blown dead vs. when the kicking team fell on it.)

What is the rule here? Thanks.

The ball is immediately dead when the ball crosses the goal line and is a touchback. Even if the receiving team muffed the ball and it subsequently went into the endzone the ball would still be dead and would be a touchback.

Federation Rules allow the ball to become dead when any kick crosses the goal line. (Except on a field goal attempt... that question is always on yearly test.

NCAA rules maintain that the ball only becomes dead wehn untouched by R, it bounces in the end zone. If R muffs the kick, it must be covered up by R within the endzone.

Cbrockett

Canadian Ruling
 

If K falls on it before the whistle, score a TD. (Ball is live in Canada until someone recovers it.)

If K falls on it after the whistle, rule as an inadvertant whistle. I'd also penalize R 10 yards for misleading tactics. 1D/10 @ R-5.

NFHS: There is no argument here. The ball should have been blown dead when it crossed the plane of the goal line. However, a whistle is only an indication of the ball being dead, it does not kill the play.

While the player had to wake up the official, the correct call was made and the ball was spotted on the 20 because a touchback occurred.