Nothing like being the head of a politically influential union to get a response when your car is burglarized. At least that was the case when Firefighters Union Local 798 President Tom O’Connor walked out of San Francisco City Hall after an afternoon of contract negotiations to find his 2010 Chevy Tahoe broken into — for the third time in two years. “They got a garbage bag that was full of my kid’s clothes,” O’Connor said. “About the only thing of value was a pair of size-13 basketball shoes — if you want to call that valuable.” One of O’Connor’s fellow negotiators suggested tweeting a photo of the damaged sport utility vehicle to show that no one is exempt from the epidemic of car break-ins — even people who park across the street from City Hall in the middle of the day.