The former NBA player was in the City for a conference with representatives at the John F. Kennedy Center for Performing Arts. He was helping an elderly man get into a cab near Union Square when someone sneaked up behind him and ripped of his garment bag that was holding a suit, shoes and some toilietires, his blog notes.
"Not the end of the world, but frustrating," he wrote.
He turned his back for 30 seconds, he says, and someone swiped the bag.
"The real crime was the vulnerability of it all," Johnson wrote on his blog, "the idea that I could leave my bag on a crowded street, turn my back for 30 seconds and have my stuff stolen."
Johnson says his experience gives him something to talk to the City's mayor about.
"Next time I see San Francisco Mayor Gavin Newsom," Johnson wrote, "I’ll tell him the story and give him my word nothing like that will happen to him in Sacramento."