Pilots flying in CAS are NOT exempt from checking NOTAMs and knowing about things which will affect their flight. Nor are they exempt from their responsibilities in avoiding any restrictions or hazards simply because they are expecting ATC to do it all for them.
I think you could try telling that to the next 100 747 pilots flying into LHR
In a radar control environment, it is just not normal practice to get enroute notams. I normally do it, not so much for enroute stuff but to discover closed runways, landing aids, or even entire airports
But the way IFR works around the world, it just isn't normally done.
I am informed that ATC get the notams each morning (or whatever) and plot any affecting their area on some map in the room. That way, when vectoring traffic, they can avoid stuff like airshow TRAs extending up into CAS. The jet pilot in his Tupolev is sure to know nothing of this - regardless of where the responsibility lies.
It's a bit like expecting pilots to read the national AIPs. In the IFR world, this isn't normally done either. You work out the routing, file it, call up the handling agent to sort out any PPR/slot issues, and fly. It is only in the VFR world where the pilot is going to (hopefully) do all this due diligence.