Nudist beaches - anatomical features

I was talking with a friend today about sex. I do this quite often, too often...some say. And an interesting question emerged. What if you were at a nudist beach (say, Lady Bay in Sydney), and you got a boner from seeing someone that you viewed as sexually attractive? It would be very embarrassing. Quite humiliating and might result in some unwanted attention...or if the authorities were particularly pedantic (and nude cops were patrolling nearby) you might find yourself in jail. Otherwise, you would probably have to hide it...by covering yourself. Roll onto your stomach so only your arse is showing is what I reckon.
Admittedly, I've never been to a nudist beach, nude colony or any other naturalist place. In fact, there are only two in Victoria. I do, however, want to go to one just for the experience of it. It's not a damaging, abusive or dangerous place as perpetuated by religious fundamentalists (who are as knowledgeable, ethical and intelligent as a hyper charged taser gun) or other conservative groups who object to nudism on personal grounds. If they have a problem with nudist beaches, then they should stay well clear any...or perhaps avoid the coastline entirely.
Certain precautions when establishing nudist beaches should occur. Measures such as extensive signposting, regular Police patrols (to stop abuse or voyeurism) and seclusive locations are rudimentary.
According to Wikipedia, the quantity of nudist beaches has actually increased worldwide, perhaps accompanying the increase in secularism and progressiveness which has by and large seen the reduction in old, archaic values such as covering your bits, tits, dicks, nips and hips up.