I have a 2002 Passat (bought new, now with about 35k miles) and when asking the dealer how much it costs to change the brakes over the phone, the dealer said that he would have to change the rotors as well. And this is without even looking at them! Am I getting ripped off?

Also, the rotors are under warranty for 100k miles if they get warped. If they are not warped, do they need to be changed?

VW has made the rotors without much room for machining. When you install new pads you really need to have them resurfaced, but usually there is not enough left to do this, thus new rotors are usually needed.