Chilli - I agree with your reasoning entirely.
From a legal perspective though an ATZ in class G airspace is class G itself if I'm right? In that respect there is no responsibility for the ATCOs to provide any seperation for VFR traffic.
I was always under the impression that you didn't need permission to enter an ATZ in class G airspace, you were just obliged to inform the ATSU of your intentions?
of this i may be wrong - and of course common sense needs to be factored in as well! but strictly speaking i think i'm right?