"I still say the figure of 100k NZ births sans SIDS cannot be simply coincidental and is worth thinking about"
But only if the figure can be substantiated. And only then if it is outside what you would expect from normal distributions compared to the probability of SIDS within the type of person who wraps a mattress.
I'm really interested to hear if the NZ government recommend it, as then presumably they would be the ones collecting figures on SIDS. But you know what, in that horrid situation contacting a company wouldn't be my priority. And I don't know what 'properly wrapped' means and who decides.
And I don't know what the underlying statistical risk would be for someone who is the type of person who wraps a mattress (i.e. are we talking correlation, or causation).
SIDS devastates families and, if wrapping a mattress helps, great. But it also leaves people very vulnerable to snake oil salesmen.
If you are just an interested layperson, I am sorry for being so hard on you. But you have no history under this username on this site and you've made (maybe with the best of intentions) some fairly sweeping statements. So people are going to come back quite hard with the other side.
I very much doubt it does any harm. So along with doing everything else (back to sleep, feet to foot, no smoking, etc), well go ahead if people want to.