I was thinking this. When I worked in London you would often see women sunbathing at lunch, occasionally in a bra but normally just with skirt rolled up a bit etc... As they are in a public place I guess its fine for people to just take photos of them?
Surely it's all about context. Like, if you're just showing a scene of people enjoying the sun, then fine. If you're zooming in on a woman because she's not wearing much clothing, that's a whole different kettle of fish. Unless you have her consent of course.