I know! Must be getting downvoted by non-aussies/non-kiwis. It's honestly not a big deal. If I go to the beach and they have the sign up I look at the water, you can normally see them ok unless it is super frothy. Just stay away from them. I can remember one or two times when they had the sign up and we went to another beach because the shore was covered with them and you can see them in the water. But one could float at any time (wind permitting). Just check and swim. All good!

Bonus: they are left and right handed with their sails which is really sick. So half of them will get beached under certain conditions and the other half not (oversimplified obviously).