New Pads and Rotors after 18K Miles???

[dadi_oh]

I am buying a used 2006 Yaris with 22.5K Km = 18K Miles (due to pick it up today). In Ontario, Canada we have a mandatory safety check on cars so as part of that check the dealer that I am buying from has informed me that they changed the brake pads and rotors. This seems like awfully low mileage to be changing pads. I do a lot of highway miles and my pads usually last me at least 90K Km.

So what are the possibilities here?

1) Defective pads originally.
2) Car was parked a lot between drives and rusted rotors wore the pads.
3) The car was used for a LOT of city driving and the person didn't know how to downshift?
4) The car has a lot more than 22.5K Km on it. Is it even possible on new cars to disconnect the odometer. I would think that would royally mess up the ECU that depends on the speedometer. (Anyone know where the odometer cable comes off the transmission? Maybe I can check the seal).
5) Other ideas?

David