Fans attending tonight's IMAX trailer presentation for Batman V Superman: Dawn of Justice won't just be walking away with free mini-posters; they're also getting passes that allow them early access to the film when it's ready to hit theaters next year.

There will be special fan screenings of the film one week prior to the release of Dawn of Justice to the general public -- not a bad perk for attending a screening event that's free tonight.

Today's events were sold out, oversold and theaters filled on a first-come, first-served basis. It's not yet clear whether fans who were able to get a ticket but unable to attend the screening will also be eligible to claim an early pass.

It appears from a cursory look at Twitter that they're handing out the passes in theaters -- which would then make them susceptible to theater employee theft, and easier to sell online because it's a physical artifact that isn't personalized for each user. Still, it's possible those physical objects are placeholders and the real, usable passes are being distributed via e-mail to people who signed up for the screenings. As of this writing, we cannot be totally sure.

When Man of Steel was in theaters, early screenings were held for a number of special events and charities -- and a Thursday evening screening the day before release for those who pre-ordered the Man of Steel Blu-ray through Wal-Mart stores. Those preorders also entitled fans to a download of a Man of Steel prequel comic that laid out the origin of the DC Cinematic Universe's version of Supergirl.

Batman V Superman: Dawn of Justice will be released officially on March 25, 2016.