MURRIETA, Calif. — Rumors had swirled among anti-immigration activists near a U.S. Border Patrol station in Southern California that the agency would try again to bus in some of the immigrants who have flooded across the U.S.-Mexico border. Instead, by late Friday afternoon, they got dueling anti- and pro-immigration rallies. The crowd of 200 outside the station in Murrieta waved signs and sometimes shouted at each other.