might be the wheel bearings. but when they took the tires off, how was the wear? how loud is it? any modifications? sedan or hatch?
Premature Wheel Bearing Failure on a car that's less than 2 years old? my money is on noisy tires, because there were Cheap tires on scoots when I got her, and when they were just about ready to be replaced, they would HOWL at 20-25MPH.