I shaved everything - I'm also blonde. But when it comes time to putting on the ProTan or whatever is your tan product of choice, it looks much smoother w/o extra hair.
I actually started it as a ritual (shaving my arms, etc.) w/ that Mach 3 razor about 4 weeks before the show. First so I wouldn't have any ingrown or any results from that first couple of times you shave a new area and also to sort of mentally go into serious pre-contest prep for the show. A little silly, but it reminded me of how close my show was and kept me focused & excited.