Maybe I'm just a paranoid parent but whenever I've been pushing one of my kids' prams along a promenade, I have not EVER let go of the handle if there hasn't been a wall or something between the pram and the sea. It just goes against all your instincts, surely, to actually let go of your children when you are right next to the sea (when by all accounts it was high tide and so it wasn't like they were just going to drop onto sand, which would have been bad enough)
I'm not sure that men have those same instincts to be honest. My DH is an absolutely fantastic husband and father - really great. but there are a couple of times when I've had to shout his name to get him to grab DS2's pram slowly rolling away down a SLIGHT slope in the park when he's been in charge of the pram. I just hope that if he was in sole charge of a pram right next to the sea then he'd consider it vital he keeps hold of the pram.
If ALL men are a bit like that, then just add a bit of distraction to the mix in the shape of a mistress and it's asking for trouble.
It's a horrible story, feel so sad for everyone and just wish it wasn't true.