Students at the University of Southern California were forced to cancel an event featuring free speech advocate Dave Rubin after administrators imposed a last-minute security fee on the event’s organizers.

Public safety officials notified the student organizers of the event that they would be required to fork over nearly $600 in additional security fees if they wanted to proceed with the event as planned.

Rubin recently starred in a popular online video for Prager University in which he explained his move away from the American political left and towards classical liberalism.

Administrators told the event’s organizers that Rubin’s controversial history “may present security issues” and that two armed guards “trained in dealing with potential disruptions or protests” would be required in order for the event to proceed.

Breitbart News has covered the topic of security-fee censorship extensively. On more than one occasion, students planning to host former Breitbart editor Milo Yiannopoulos were hit with last-minute security fees that made it nearly impossible for the events to take place as scheduled.

Tom Ciccotta is a libertarian who writes about education and social justice for Breitbart News. You can follow him on Twitter @tciccotta or email him at tciccotta@breitbart.com