It does have a ring (groan!) of truth to it. Every now and then, there are stories in the media, here in Australia (you'll be able to attest to this, Sue) about small children being disemboweled when they sit on the filter in their backyard swimming pool. Haven't heard about any such incidents for some years now. The manufacturers have probably put mesh covers of them. At one time there, not a summer would go by without the story emerging of a toddler being killed in this dreadfully gruesome manner.
Yes Kerry, I was gonna mention that myself here.
I would assume that all swimming pools are now fitted with filters that do not allow this to happen.
It was the round hole on the swimming pool edge, where the skimmer basket is, and where people can connect the vaccuum for the pool. They are fitted with lids now, but the lid is still easy to take off, but maybe not by a little one. There is still a hell of a lot of suction there. I think little ones used to think it was a potty, somewhere to do a pee.