"I think the NFL’s really cracking down on fan behavior both inside the stadium and outside,” Costner told the Los Angeles Times. “The idea of hanging somebody, for as funny as I thought it was, and as realistic as I thought it was, it was just an image that I didn’t want in the movie. That was a small price for us to pay, but it shows that they were watching very closely.”
The NFL has a history of watching closely. It's no accident that almost every football movie you've seen features fake professional teams and logos — The Replacements, anyone? The NFL is notoriously protective of its brand. However, the league's willingness to let filmmakers use real teams and logos increased Costner's enthusiasm for the project.
Burning effigies, though? Too real. (NBC Sports speculated that the NFL didn't want to give fans any ideas).