Britney Spears was out of sight but not out of mind Wednesday, as speculation turned to what will happen now to the young children of a pop diva and single mother who can’t seem to stay in rehab for more than a day. Spears left the Promises Malibu Treatment Center on Wednesday, according to “The Insider” TV news magazine, less than a day after arriving at the center. Last week she reportedly sought treatment at a center in the Caribbean but also checked out after a day, returning home to Los Angeles, where she was seen shaving her head bald at a hair salon and getting a tattoo on Friday and at several night spots over the weekend. OK! magazine reported it had learned Spears fled rehab on Wednesday because she was worried her estranged husband, Kevin Federline, would move to obtain permanent custody of the couple’s two children, 5-month-old Jayden James and 17-month-old Sean Preston. “He physically has the kids right now. His mother has flown in to help,” Mary Ann Norbom, the magazine’s West Coast bureau chief, said, citing a source close to the Spears-Federline families. 160Want local news?Sign up for the Localist and stay informed Something went wrong. Please try again.subscribeCongratulations! You’re all set!