'R' -- Hollywood's Scarlet Letter

July 28, 2008 — -- Slamming a head into a pencil; holding a knife to a pair of scared, quivering lips; shoving a gun into a mouth and pulling the trigger.

And yet, no R rating?

It's a puzzling thing about "The Dark Knight," which is no doubt the darkest movie in the Batman franchise. The film is rife with violent scenes and drips with the Joker's yellow-toothed menace. Yet it bears only a PG-13 rating, the same sticker slapped on "Mamma Mia!," whose most offensive scenes are arguably those of Pierce Brosnan singing.

The reason? R is increasingly becoming Hollywood's scarlet letter, the rating no would-be blockbuster wants. It scares parents and cuts out the whole swath of under-18 movie goers. If it means higher profits, studios have no qualms about lobbying the Motion Picture Association of America (MPAA) for lower ratings. And often, the MPAA has no problem granting their wishes.

"Think about it: When have you seen a comic book movie about a superhero that got an R rating?," said Eddie Schmidt, who produced 2006's "This Film Is Not Yet Rated," a documentary about the MPAA's notoriously secretive rating system. "The system is self-regulated: it's set up by Hollywood for Hollywood products. So it's in their best interest for films to get PG-13 ratings."

"For PG-13, they gave the rating reason, 'intense sequences of violence and some menace.' But what does that mean?," he continued. "PG-13 is obviously stronger than PG, not as strong as R, but what's actually in the movie? What is 'some menace'? It's unlikely that you're going to get any info that's going to prevent you from seeing it, even if it's info that's helpful for parents. You might read more information about the movie and not want to go -- therein lies the issue with [the MPAA] giving out information."

The MPAA did not respond to ABCNews.com's requests for comment. Schmidt speculated they probably screened multiple versions of "The Dark Knight" before giving Warner Brothers the rating they wanted.

"Generally you submit a cut and then they come back to you with a preliminary rating," he said. "And a lot of times there is back-and-forth between the studio and the MPAA to try to get what would be a more desirable rating. Studios obviously have a lot of resources; they can resubmit multiple cuts with small changes here and there to get the rating they want. It's not unheard of for a studio to submit 9 or 10 different cuts to get the rating they want."