Why do we need to adopt this guidance given there are lifeguards on duty? Surely this is their job?
You’re right in that the role of the lifeguard is to prevent accidents. But the intention of the guidance is not to reduce the number of lifeguards supervising swimmers.
It is to help the lifeguard whose duties are not only rescue and immediate first-aid but also the anticipation of problems, intervention to prevent behaviour which is unsafe and the education of users in relation to water safety generally.