In the movie "far and away" , in the boxing scenes, they drew a chalk line on the floor and a little boy screamed "toe the line" and the boxers were not supposed to step over it toward each other. The kid was played by the kid who played Crutchy in Newsies. Not sure how accurate it was.
It's a movie built on the idea of romantic chemistry between Tom Cruise and Nicole Kidman, so I'd take anything it proposes with a grain of salt.