For years, federal agencies have struggled to rein in the abuse of government-issued credit cards. In one instance, federal employees were even billing their agency for BMWs and home theatre systems. Federal auditors say even today, departments are failing to provide proper employee oversight—leaving millions of dollars vulnerable to waste and abuse. The latest report comes from the Department of Transportation’s inspector general, who estimated that in 2012 alone, employees charged more than $2 million in unauthorized travel expenses.