Siri Masterson, manager of the horseback riding business behind Polo Beach, recently made a presentation to the Oahu North Shore Neighborhood Board to complain about nudity and alleged sex acts which she observed there.
Recent media coverage:
Hawaii News Now: http://www.hawaiinewsnow.com/story/21803625/concerns-about-nudity-sex-acts-at-beach-in-mokuleia
The Hawaii Supreme Court precedent, State of Hawaii versus Kalama, established the right to nude sunbathing here (and presumably other locations):