scrimmage kick

[Brett]

In this situation, I blow it dead (provided the ball is stopped) as soon I make the determination that R is not planning on fielding it.

[bcl1127]

I believe that in this case you can use the rule that states a ball becomes dead when it is motionless on the ground, and blow the play dead there. There is no requirement for K to down the ball. Once the ball is at rest, the play is over. I am using your scenario above where there is no R player near the ball.

[DesertZebra]

Yes, blow it dead when there is no play being made on the ball. Same thing for balls that are 'first touched', if the ball after being touched lays there with no one from R making a play on it, blow it dead, rather than waiting for someone, either R or K, to pick it up.