Indonesia's surprise plan to roll out a nickel-ore export ban two years early could scare foreign investors away from Southeast Asia's biggest economy, analysts say, as it cements a reputation for policy flip-flops.Nickel prices soared this week on supply concerns after Indonesia, the world's top producer, announced the ban would start next year instead of 2022 in a bid to process more minerals at home.Ending exports of bauxite, used to make aluminium, and copper concentrates i