well, people might pretend to be offended C5, but i think this is only the case if you are openly goggling the person and being really blatant.
of course people realize you're going to be seen on a nude beach!
i have gone in the past (in Germany) where it's customary to arrive with your clothes on, and picnic basket in hand, and then just undress right there on the beach...no towel wrapped around your waste!
i've looked, and certainly been looked at, but unless someone is sporting wood, it's not that big of deal (and it's not like i go there to be looked at, as things are pretty normal down there). i have seen a guy with a hardon once, just walking around (and yes, around children), but everyone just acted naturally and assumed "oh well, it got a boner...it happens!"
so, i think that if you're there, and want to participate...go for it! if not, there are some beaches (again, in Germany) where you can still wear your suit, even if others are nude.
but one word of advice: don't take pictures with your camera