Repeat customers, prized by most businesses, are becoming costly headaches for Central New York hospitals. That's because the federal government is now penalizing U.S. hospitals that have too many "frequent flyer" patients. Hospitals with above-average rates of patients who come back within 30 days of their last hospital stay are seeing their federal Medicare payments reduced. The penalty will cost Central New York hospitals about $3.3 million over the next year, according to the Iroquois Healthcare Alliance, a hospital trade group. Nearly every Central New York hospital is being penalized, with St. Joseph's Hospital Health Center in Syracuse facing the biggest hit—an estimated $875,000.