I just picked up my A4 prestige and noticed rust spots on the rotor hub (where the brakes meet the wheel rim). Is that normal? Or should I take it back to the dealership to have it looked at?

 

Its normal when a car stands around for a long period of time. The morning dew along with rain can create that rust. Luckily, if that dust is on the rotor itself, this problem will fix itself once you drive he car for 100 miles or less. If its on any other parts, you will have to bring it in so that they can clean this manually. Nothing to worry about safety-wise.