I had a good laugh today at Don Demsak’s strategy for reducing telemarketing calls and increasing telemarketing companie’s costs.
I have tried a couple of different strategies myself. The strategy I find that works best is to tell them that by law if you ask them to take you off their phone list they have to do it and that they have to keep their own list of people that don't want to be called back. They usually end up hanging up on you right away.
I have also resorted to using SIT tones (You can get them here: http://privatecitizen.com/sit.html) before my answering machine message plays to try and counter act computer dialed telemarketers. Since I have added the SIT tones I have noticed a considerable decrease in calls by telemarketers.