Are you suggesting that with the pre 1990 system such incidents did not place?
I would say that in the "pre 1990 system" the Pitts would probably have advised FS that FYI he was conducting AWK/aerobatics NOSAR - or possibly asked for skeds - but either way the Dash 8 would then be informed re the presence of the Pitts.
VFR weren't entitled to a TFC info service outside an AFIZ, but the Pitts would probably been given by FS a "For info, ABC a Dash 8 inbound ..".
These days because VFR particularly NOSAR have been scared off - indeed actively discouraged by certain parties - from talking to ATC or broadcasting on area frequencies, the self-announcement may not happen.