I think we've all taken the wrong approach to the phone spam problem.
Whenever I get a scam call, I always answer. I let the guy do his spiel about the free vacation he's got for me, then when he asks me for my credit card, I hit him with one of the ligma jokes [0] and hang up. Never takes more than five minutes of my time and it's a source of great joy for me. I've gotten the same guy three times and he's fallen for it every single time; at this point I'm starting to develop a bond with him.
If we pushed a social movement that popularized this, we could basically DDOS phone scamming out of being viable.