I've occasionally seen damage to the nose tires due to improper use of the push tug here in CLT. Guessing IAD may use a towbarless tug that lifts the nose gear off the ground for push. If the ground crew is not paying attention, or trying to push the scoop under the tires (instead of using the winch to pull it into position), the lift plate can put a good gash across the tire tread.

As an aside, the ramp crew can damage the tires with a towbar also. Usually rips a chunk out of the rim if not disconnected correctly (unhook and remove without disconnecting the tug first).