In its quest to keep fans in the stands, and give them a reason not to view games in high definition in their livings rooms, the N.F.L. will put cameras into all home team locker rooms next season. Then they will encourage the teams to use the video on their stadium scoreboards, to give fans who buy tickets an inside look at what goes on in the teams’ inner sanctums. The N.F.L. is mandating the cameras, not making them optional, said Eric Grubman, the league’s executive vice president, during the opening panel of the IMG World Congress of Sports. Sports Business Daily first reported Grubman’s announcement from the panel. Forcing the cameras on teams is probably a good idea, considering that notoriously secretive coaches would probably have strenuously resisted it as a suggestion, even though teams can use the video at their discretion and are unlikely to reveal any significant strategic details. The league is also mandating that replays of important plays – fumbles, scoring plays, catches on the boundary – be shown in the stadium, even if the replay may not show an outcome that is favorable to the home team. In many stadiums, replays are withheld if they would help the away team, particularly because coaches have adopted the habit of looking at replays on Jumbotrons before deciding whether to challenge a play.