Nope, perfectly safe to polish them but they'll look like hell after about 5 minutes of street riding. It's best to polish them, get them installed, and take as many pictures as you can of the front end BEFORE you take off on a ride.

 

I chucked my rotors up on a lathe. Used gradually finer sandpaper down to 2000 grit. Finished up with jewelers rouge. Went pretty well. But mine have dulled where the brake pads contact the rotor surface. Might not work as well with the sensor in the rotor. My bike is older and the rotors have no protrusions. I realize not a lot of people have access to a lathe.