Two San Francisco residents, one of whom is disabled, are furious with what they see as an unjust parking ticket, and they have taken their complaint to federal court. The lawsuit -- which was served Sept. 12 to The City, San Francisco Municipal Transportation Agency and one of its citation review officers, and the Police Department, its chief and the officer who issued the citation -- claims the Feb. 16 parking ticket was unlawful. Although the fine has been greatly reduced, the plaintiffs have decided to press on with their complaint.