I tried to discuss this at a "car seat safety" meet with our MOTS (moms of tots) group a couple years ago. Another mom, who says she knows a lot about car seats, basically said I was crazy - both about not wearing coats in car seats and about extended rear facing. She said that our insurance (public insurance, they have "car seat technicians"... but they're going off old info) doesn't recommend those things, so I must be wrong. Even though I had car seat info from both that same insurance and from the government of Canada's transportation department that talked about those very things.
And never mind that the car seat manuals themselves ALL talk about not bundling baby up in heavy/thick coats.
The argument the mothers gave, over and over, was that it's just too cold here to expect that to be safe, and that obviously the people recommending it don't live here.
Yes. It is cold here. But we haven't had coats on our kids in their seats for years now, and they're all just fine - we buckle up, and they pull their jacket on like a blanket.
They also argued that in an accident, you'd have
to be wearing your coat, at least, to be safe in the cold.
One mom told me that she always
has her daughter in snow pants and her jacket when it's cold - then buckled in her seat!? It would be SO loose!
I talked to them about compression of the coats, and asked if they noticed how much they had to adjust the straps with/without coats - they all said they noticed that, but refused to acknowledge that the clothing would ever compress and "make" the straps that loose. Again