"Concussion," out Friday, stars Will Smith as Dr. Bennet Omalu, a Nigerian doctor who discovered the brain disease chronic traumatic encephalopathy, better known as CTE, which has become a hot-button topic related to football in the past few years. More and more of the game's players (from professional to recreational) have described having symptoms associated with CTE. In "Concussion," Omalu attempts to raise awareness of the disease as the NFL tries to cover it up.

For the sake of authenticity, the movie is filled with shots of boardrooms with the NFL logo and authentic team logos prominently displayed.

NFL is clearly not outwardly endorsing a movie that shows it attempting to sweep away an issue that could cripple its business. So why is "Concussion" legally allowed to show copyrighted material without the league's consent?

According to entertainment lawyer Michael C. Donaldson, as long as the use of the NFL trademark and team logos does not in and of itself disparage or misrepresent the brands, there is no need to ask for permission.

Donaldson, who has over 30 years of experience in copyright and entertainment issues, told Business Insider the NFL "browbeat a lot of people into paying fees that don't have to be paid." He added: "They extract those fees from filmmakers who are either nervous or not completely aware of their rights under the law."

Donaldson gave this example in how to understand trademark law:

"It's all right to say, 'This Coca-Cola tastes awful.' You can say, 'I hate Coca-Cola.' What you can't say is something that misrepresents it, such as you drink a Coke and you drop dead and someone says, 'That happens all the time.'"

What causes the confusion, Donaldson said, is what goes on at the networks. Because they air NFL games, they have broadcast rights. You may notice the disclaimer during games that says in part, "Any pictures, descriptions, or accounts of the game without the NFL's consent is prohibited."

"So people think, 'Oh, the networks pay for the use of logos, obviously I have to,'" Donaldson said.

But that is different from trademark rights.

For example, in this scene in "Concussion," the NFL logo is prominently shown as a backdrop during a news conference:

But because the logo is shown in a way that does not misrepresent its real-life use, the depiction is completely legal.

The issue of using material copyrighted by the NFL also came up earlier this year during the premiere of HBO's new show "Ballers," starring Dwayne "The Rock" Johnson as an NFL player turned agent. As with "Concussion," the show uses the NFL logo and team logos throughout.

In the opening scene of "Ballers," we see Johnson's character, Spencer Strasmore, having flashbacks from his days on the gridiron as a Miami Dolphin. He's wearing a Dolphins uniform with the team's logo in plain view. He's chasing down a Buffalo Bills quarterback, whose helmet logo is also clearly visible.

Donaldson said the show's depiction was legal.

According to Donaldson's partner at his practice, Chris Perez, the show can go even further, and the NFL could still not have a case.

"One thing that we can say for sure about players in the NFL in the last few years is that fights happen on the field every so often and then they get broken up by referees or coaches," Perez said. "Players have engaged in domestic violence and then been convicted of that, and NFL players have committed murder. So you can create a show that uses NFL logos and create a fictional situation where all of those things happen."

Later in that episode, the show does depict a player in a negative light. A fictional star receiver for the Green Bay Packers, Ricky Jerret (John David Washington), gets into an altercation with another man at a nightclub and beats him to the ground in front of everyone.

John David Washington as brash receiver Ricky Jerret in "Ballers." Jeff Daly/HBO/"Ballers" Though the NFL surely doesn't like that scene, Perez says the show is within its rights to air it.

"Where you can get into trouble," Perez said, "is portraying how the NFL reacts to it. The response has to be consistent to how the NFL would react in real life."

According to Donaldson, if there were a scene in which someone playing the NFL commissioner held a news conference and said the NFL wanted players to get into fights at bars, the show would "get into big trouble." (The NFL had "no comment" for this story.)

Jerret's actions in the episode do not go unpunished. Following the altercation, with the Packers logo in full view, we see the general manager say "cut him."