Speedos at a nude beach

[Torchwatch]

There are many answers to your question making it difficult to give a short concise answer.
A nude beach is a fairly safe place as it will tend to drive away all those who object to the naked human body. All those who mock, point and make unpleasant comments will remain on the board shorts beach.
Having driven away the intolerant a nude beach attracts several different categories of user: families with children, (mixed) couples, single men and gay groups. The gay groups may be formed of single men who merge together.
Some single gay guys wishing to enjoy meeting other gay men may be attracted to nude beaches but prefer to wear speedos rather than go naked.
Other men that choose to wear speedos or swim thongs may find the main town beach overcrowded and unwelcoming and head off for the more tolerant and peaceful nude beach.
Some people wish to experience a nude beach but when they arrive they are too nervous to strip off completely, so remain in speedos.
On a beach in France close to a major naturist resort I came across a young man who had hidden his kit in the dunes then walked around the tops of the dunes and into the woods wearing only black speedos and sandals. He would promenade in plain sight until naturists started walking towards him to have a closer look, then he would disappear into the dunes or the trees only to reappear in a distant yet highly viewable spot. I am not sure if there is a word for this behaviour.