Someone posted a link from 2013, so some of this info is outdated. Some of it might be different approaches in different cultures and countries. And people just love being right, don't they, and they love getting angry when it's for the 'protection of children'. Especially when they think the opponent is a 'dirty hippie' following any kind of non-mainstream woo-woo ideas. I'm just sorry for their kids. A baby is a small mammal and their sense of safety directly derives from closeness with the caretaker. Babies who feel safe are more likely to turn into adults who feel safe.

I agree. Unless we're drugged, we're far more aware of our surroundings when asleep than most people realize. It's very unlikely that an undrugged person would roll over onto a baby and suffocate it.

Are you unconscious when you sleep?
The short answer

No, you are not unconscious when you sleep. You are in a state of reduced consciousness that is fundamentally different from medical unconsciousness. A review in Nature Reviews Neuroscience described sleep as a "reversible behavioral state of perceptual disengagement from the environment." That is a critical distinction: you are disengaged, not disconnected.

Your brain can still process external stimuli during sleep. A parent wakes to their baby's cry but sleeps through louder ambient noise. You respond to your own name spoken softly but ignore a stranger's name at the same volume. These selective responses are impossible in true unconsciousness.