Warrany Service Problem?

[2009Yaris]

I recently discovered a scrapping sound on my Yaris when the steering wheel is turned hard right. The dealer that I have servicing the car informed me that the rotor is rubbing against the backing plate. He also quoted a price to fix the problem. Confused, I told him that the car still has less than 36K miles on the odometer; therefore, the repair should be covered under warranty. He then tried to say that the guy who replaced my pads caused the problem, which was news to me because the car still has the original pads. He retorted that the pads could not be the original pads because they looked new. I know for a fact that the pads are original, that is, unless they were replaced by the brake fairy in the middle of the night. The reason why they look new is because I am a very conservative driver (i.e., I drive like an old man), and 95% of the mileage on that car is highway mileage. Has anyone had this type of problem with their Yaris?

I guess that I should have caught this problem sooner. However, I rarely make turns that require turning the wheel hard right or left, and the sound is easily missed with the windows rolled up and the radio on. If push comes to shove, I will pay for the repair, but I will send a nasty-gram about my experience with the dealer's service department to Toyota Motor Sales, USA.