I have often though about such things myself, although I don't underdress if someone medical was to examine me they'd soon notice that I shave most of my body. I've come to the conclusion that it doesn't matter, they're not going to ask you why, no one asked me why when I had to go in to have my appendix out, although only my legs were shaved back then. My wifes, cousins daughter is a nurse, spent a lot of time working in Casualty, something like that is the least of their worries.