I can only strongly confirm this: last summer, my 2.5 years old boy fell in a (private) swimming pool while playing around it. Of the 4 adults that were around

I can only strongly confirm this: last summer, my 2.5 years old boy fell in a (private) swimming pool while playing around it. Of the 4 adults that were around the pool (less than 3 meters away), only one saw him and could get him back safely. We could not hear a single noise, no cries, no water splashes... Although he was wearing those kids armbands, they were useless as they were keeping his head underwater (he fell head first). The whole thing took less than 5 seconds, but it was really frightening in retrospect. Do not break line of sight.