YES... I.e.: if you are on the national DNC registry, and an automated telemarketer keeps calling you, the best thing to do is have the state att'y general mail them a letter, and eventually this will actually scare them enough to stop calling.
I'm finding that if you just let them roll to voicemail, they stop calling. If you even once pick up an press any of the buttons, they know they have a live number and they keep calling.
I recieved a call from 1-860-216-2292 on July 15, 2008 at approx. 9:13 a.m. I did not recognize the number and did not answer. If its legit, they will leave a message. No message was left.