I friend of mine told me that a guy from the LBS told her to tell me that I need to take my bike inside while I'm at work and not leave it on my bike hitch. He said that the sunlight would degrade the carbon fiber and that it could cause it to crack.

I've done a little searching online and found some pages that suggest that unpainted carbon fiber will degrade in sunlight. My bike is painted. So, is he right or full of beans?