U.S. safety regulators received a complaint about a Chevrolet Camaro driver accidentally shutting off the car with a knee more than a year before General Motors on Friday recalled half a million of the sports cars over the issue, which is similar to the defect linked to 13 deaths in older GM small cars. Regulators have received at least 18 consumer complaints since 2009 about Camaros involving engines stalling or sudden loss of power, a Reuters review of a National Highway Traffic Safety Administration database showed.