This image could as well mean - Respecting boundaries, for the safety of others.
Just like your friend pointed out, that swimmers' disregard for boundary has left a gap in the swimming pool that could compromise the safety of others pool users.
We love to push beyound borders, but sometimes for the good of all, we might as well respect boundaries.
Thanks @oluwoleolaide for this post.
I love your view as well my friend, thanks for the great input mate.