Tarp in Live Ball Territory

[DRJ1960]

Tarp against fence well away from fair territory down 3rd base line. Home coach wants to play surface of tarp as "live" unless the ball enters the roller or goes between fence and tarp. All agree that standing on tarp puts you in dead ball situation.

Partner declares that "The Rule" is that if any player touches the tarp with the bottom of her foot, she has entered dead ball territory.

I'm cross eyed reading rule 5. Closest I can come is when you have a foot completely in dead ball territory.

(I am aware that the Umpire sets the ground rules... just looking to find his "always" regarding a tarp).