I answered. Automated robo dialer informing me that my vehicle warranty has expired and they have sent the final courtesy reminder. This was my last chance to reinstate my vehicle warranty. When asked if I wanted more info, I answered 'no' a few days ago, but today answered 'yes' and they still hung up on me.
The reality of the DNC list is that it stops only those law-abiding businesses from spamming you with solicitation calls. Robocallers (which in and of itself is illegal), unscrupulous US-based businesses, and pretty much any non-US based solicitor will not register with or abide by the DNC list. So Mustanglady is correct in saying that you would get significantly MORE calls if you are not registered on the DNC list.