Little did I realize, but tampering with the ball happens a lot. And it's not hard to do as the ball naturally gets scuffed up during a match because it gets bounced on the ground all the time. The BBC story linked above explains a lot about what happens when a cricket ball is tampered with. It's almost like a pitcher throwing a curve ball during a game that suddenly decided to break the other direction.
As I see it, if there's a ball and a bat, it's fair game for the Griddle.