Spring breakers hoping to party all night were corralled off the streets of Miami before midnight by cops on souped up golf carts. The city put a 12 a.m. curfew in place after a streak of violence including a shooting that sent revelers running last week. Even during daylight hours there is a heavy police presence, and when the clock strikes midnight, an eerie calm descends over the streets - a far cry from the mayhem just a week ago.