SAN ANTONIO -- Eleven "Mad Max" fans were arrested after alarming motorists as they made their way to a movie marathon in a theatrical convoy in which they surrounded a tanker truck armed with fake machine guns.

As the group was headed to San Antonio from nearby Boerne Saturday morning, police received several calls from motorists who reported a "militia" surrounding a tanker truck, a police report states.

Police charged nine people with obstruction of a highway and two others with possession of prohibited knives in addition to obstruction of a highway.

One of the organizers of the convoy, Chris Fenner, said the arrests were unfair. He said he didn't know why anyone would have confused the costumed crew recreating a scene from "Mad Max 2: The Road Warrior" -- set in a post-apocalyptic wasteland -- with a real threat.

About 25 people participated in the convoy and more than twice that number were expected to attend the movie marathon, which was canceled after the arrests.