Trivia: The town in Iowa that the movie was filmed in was Dyersville. The actual house and farm used in the movie are about 2 miles outside of town and are open to the public.
Trivia: Then unknown, Ben Affleck and Matt Damon are among the thousands of extras in the Fenway Park scene.
Trivia: During the filming of the cornfield scenes where Ray first hears the voice, the filmmakers had problems with the corn growing. When they initially wanted to film the scenes the corn was too short, so they waited a couple of weeks. When they were ready to shoot, the corn was too tall. Kevin Costner had to walk on wooden planks, so he could be seen in the cornfield (Director Phil Alden Robinson discussed this in the 10th anniversary edition of the film).
Trivia: At the end of the movie, where you see the cars driving to the Kinsella's house to see the ballfield, it's actually a bunch of cars lined up for miles and to give the illusion the cars are moving, the car owners are flashing their headlights.
Trivia: The film uses Galena, Illinois as a stand in for Chisholm, Minnesota. Galena is just about 45 miles from the main house and field in Iowa.
Answer: If they go past that line they will no longer be able to play again. The field is their only place to exist in the afterlife (their heaven if you will). That line is the end of the field and they will not be able to return if they cross it.
Scrappy
So do the players not go after foul ball fly balls/pop ups along the first base side?