I assume they checked to make sure the valve stem wasn't leaking. I had the same problem with my snow tires and the stem was the prob.

Never heard of a rim leaking, but that doesn't mean it isn't possible.

1998 Silver Frost SVT Contour born on...8/28/01[/i]
American Iron Shootout Radial Tire 2 Class Champion, Cecil County Dragway April 20, 2002