I remember listening to an NPR show where a doctor talked a lot about this, and how all of the shaming of co-sleeping might contribute. She claimed a non-obese, non intoxicated parent sleeping with the child on a bed isn't all that dangerous. That same situation on a couch is deadly. But the messaging is more abstinence than harm reduction, so all many people hear is "co-sleeping is dangerous"

Consequently, exhausted parents accidentally fall asleep on the couch holding their babies when they would have been better off just lying down and napping.

If you know the cause it is not SIDS, by definition, right?