Good points, yeah it would probably better to do something like what you're talking about.
It's pretty rare that I get scam calls, there's a do not call list in the us you can add your number to. When I do get a scam I always ask where they got my number, and tell them to take me off their list and to tell the list provider to take me off their list. Or if they tell me the list source, I follow up with it and try to remove myself