Not totally nude, but topless.
My ex GF used to occasionally go topless on one of the bayside beaches here in Melbourne. Normally, we would choose a time, or location, that meant there wouldn't be many people around - e.g. late summer on a week day. There might be 50 people on the beach, but pretty scattered about.
This one particular day, I was in the water, looking back to the shore. My GF was laying topless in a spot where people weren't walking past, but I noticed a younger guy - probably late teens - deviate his path by 40-50 metres, and slowly walk past. You didn't need to be a genius to work out what he was doing
When I came back out of the water, I asked my GF if she saw the guy walk past & she replied 'yes'. I told her what he did - she didn't care one bit. She was what I would call a closet exhibitionist - she knew the effect her boobs had on people & enjoyed the attention, but never made it obvious - which was just as I liked it.