pitching screen

[Ran.D]

Got to the park last night and there was a screen in front of the pitcher's mound. Handed out rules - Hit ball contacts the screen it's an out, thrown ball same as if it goes out of play.

Anchor allows screen to slide back and forth for right and lefthanded pitchers. Things went fine til the third game. Right handed pitcher insists on pitching from the left side of rubber. Sets up two feet off the rubber and goes nuts when I tell him a foot has to be in contact with the rubber.

Anyone else dealt with this? May be a good idea to protect the pitcher (one still took a shot), but it is a pain.