If you're anything like me, even though signs like these are fairly prominent you've probably never read them - and in this case would be confused when lifeguards start waving at you as you bob about the ocean beyond the marker flags.
So, when visiting beaches like Camps Bay, keep an eye out for the marker flags, and try staying between them. And remember, if you're looking for a hot date with a hot, well-built lifeguard - swimming outside of the markers isn't the way to get one. That stuff only works in the movies. ;)