This tread inspired me to do a little reading. If you google 'carbon fiber UV damage' the third item that comes up is a pdf of a paper (Kumar is first author; I'd link to it but it's a pdf). What this paper found is that there is a synergistic effect between UV and moisture exposure, with the combination greatly speeding up the loss of CG strength in the support matrix. Basically, real world bicycling conditions are bad for unprotected CF (yes, I realize they only tested one particular CF formulation) unless you live in a very arid environment.

For CF forks with a good UV-blocking clearcoat, or even better, a good paint covering, this is largely irrelevant. But it made me think about CF handlebars, which are exposed to the sun (and moisture and sweat) at their most vulnerable portion (around the stem clamp). Bars are rarely painted, and whatever clearcoat many of them have also seems very thin, and could easily be worn off my routine handling.