I think there has to be some dramatic oversimplification in the description though. Telecom signaling is still a network level event, even in mobile networks. The receiving network does not typically provide audio to the caller until the call is complete.
But hey, what a terrible idea! I'm glad to have been old enough in that period (2004-2008) that no one I knew would foist such a thing on a caller.
That being said, there's certain a lot more that could into making a system like that easier for developers. One thing that springs to mind is tooling that can describe what rules are currently in effect that limit (or grant, depending on the model) permissions for something. That would make it more clear when there are overlapping rules that affect the permissions of something, which in turn would make it much more clear why something is still not accessible from a given context despite one of the rules being removed.