> I wouldn't let a small child I am responsible for go into a pool alone
You would. Let me give you the scenario: you're home alone with the three kids, you've been chasing them around, doing laundry, cleaning up spilled grape juice, telling Jenny to stop cutting Tommy's hair, etc. Finally, you think everyone is down for a nap. You turn on the game. 5 minutes later, 5 minutes, you think "It's too quiet...". You get up and walk around for a couple minutes to find 4 year-old Sally's door open. No Sally. Where's Sally? Sprint around the house, run down to the kitchen, look in the back yard, and she's face down in the pool. You immediately get her out, desperate. You realize you have to separate from her to call 911. She's been unaccounted for by now for 12 minutes.
The paramedics get a breath back, but anoxic brain injury has set in. She dies, tubes in every orifice, 3 days later.
I have seen this play out more than once. My parents had a pool. I was a lifeguard, have made rescues. I was also on swim team, I'm in the Navy now, and I'm a physician. I surf, I dive, I do open ocean swimming and triathlons. I've helped rescue a diver in pulmonary edema. I think I wouldn't leave my kid unattended, but I know I might.
I've met the parents. They wouldn't let a small child go into a pool alone either.