Why not? Why wouldn't a legal play be appropriate? Are they trying to win? Do they keep score? If they time it and keep score and declare a winner at the end... then it seems like all legal plays ought to be permitted. Otherwise where would you draw the line? Virtually all football plays are an intent by the offense to do something the defense doesn't expect and the defense trying to do something the offense doesn't expect. "Trickeration" is part of the game.