The main issue is that it is very hard to perform CPR on an infant whilst it is attached to the mother as you need a flat surface and space to do that. So in an emergency situation the cord will most likely be but to allow access to the infant if someone is available (other than the mother) to commence CPR. If the mother is home by herself then CPR can be commenced between her legs if she is focussed enough to do it. However an OB in (I think) the UK has designed a resuscitation table that can be moved to a close proximity to the mother to allow CPR without clamping and cutting the cord but these devices are few and far between.
Ahhhh okay. See I was assuming placenta was already out (silly assumption, didn't think, DD's came quickly so I applied that to every situation, oops!)