Perth’s situation was unique in that TVW7 and STW9 joined forces to form a single company to purchase programs from the east coast, to avoid them bidding against each other which would have sent costs upward. I imagine the eastern states channels hated it but what could they do?
In the 1970s there were many examples of shows appearing on opposition network channels in different cities. In Adelaide, SAS10 seemed to be somewhat on the outer with its other network partners at various stages (including very publicly just prior to its launch in 1965) so they appeared to have rejected some network shows which got picked up by other channels. I guess that’s how it worked. If the network partner didn’t pick up a show it would be shopped around to the other channels to see who’d bite. Networks didn’t quite exist like they do now with each station in each city having a lot more autonomy.
Another example was the 1974 talk show With Margaret Whitlam. It was made by HSV7 in Melbourne and picked up by other Seven Network channels, except ATN7. So the show ended up getting picked up by Ten in Sydney.