A man who had been seen around San Marco naked in broad daylight so often he was nicknamed the San Marco Streaker was arrested Thursday evening. John Robison, 40, was arrested at his Westside home and charged with exposing his sexual organs in a vulgar or indecent manner. One of the most recent sightings was in the church parking lot behind Pizza Palace and Beach Diner in San Marco Square. Others sightings were near Baptist Medical Center. In each case, witnesses told investigators that a man was standing naked, in some cases touching himself inappropriately.