This has happened. Some people are just very deep sleepers. We’ve resorted to co-sleeping on occasion, but I’m not about to pretend that I feel great about it.

I have various other sleep problems, but fortunately none of them are caused by/cause me to move while asleep, not even so much as rolling onto my side.

But a great many people are not so perfectly immobile, sober or not, and if you haven't had a problem with rolling off a sleeping surface or breaking things by moving in your sleep, you likely won't consider it a risk.

(I'm a parent of a two month old in the Netherlands.)

Pediatric associations mostly don’t like it because it seems improper or too slum-like to share a bed with a baby. The opposition to cosleeping isn’t based on actual relative danger or long-term outcomes.

This is untrue.

Keep in mind how many mothers there are, and how many of those rare incidents had extenuating circumstances (substances, atypical neurology in the mother.) Keep in mind how easy and cheap it is today to extend the width of a bed with an attachment.

I know that the downvotes come from people who think of mothers sleeping with their children as poor trash—it’s a seriously outdated view that hurts the child.