It seems like spotting drowning children could be a good use case for computer vision, at least as a backup. The heuristics for a drowning child are pretty marked, but they're hard to spot for humans distracted by lots of other stimuli.
Yes, that doesn't look great - I assumed when I saw it was underwater that it was effectively looking up at the people on the surface and detecting people in distress from that angle. On closer inspection that doesn't seem to be the case.
It'd be a tool that can warn the lifeguards in the event that they didn't notice the drowning, not the only thing that monitors the pool.
Even the camera manufacturer wouldn't be immune from defending themselves.
Welcome to America.
When I took a 5yo to a pool which had multiple lifeguards I put her in a lifejacket and stayed within arm's reach of her. Playing in a pool is great fun but it is very high stakes. No way I am going to leave a child in such a dangerous situation and hope it works out. Making sure your child survives a trip to a pool is your responsibility.