Was Britney Spears really causing "chaos" at a Los Angeles restaurant this week? Her rep is slamming a new report! According to TMZ sources, the pop star enjoyed a night out with a man and woman at the Blue Dog Tavern in Sherman Oaks on Wednesday night. But according to their eyewitness, things allegedly got out of hand fast as she caused a chaotic and "kind of sad" scene at the establishment. Insiders claimed Britney was raising her voice, screaming, and even barking during the evening.