A more likely danger is that a non swimmer is drowning and grabs onto another child and drags them underwater or tries to climb on top of them. This is a known danger and is a standard part of lifeguard training in the US. Drowning persons can be very dangerous to other people and to rescuers. So a drowning child can definitely endanger other kids.

I was a lifeguard for a decade bud, I’ve seen it all.

Maybe you should stop being a dick.

Cmon, we're not considering nuclear war and drowning in the radiation soaked pool ?