Well, I like the idea, but I don't think it will stop those telemarketers and spammers. I personally choose to ignore them now. Or, if you have time, I just read a good information at
http://www.whycall.me/news/my-4500-payday-from-a-telemarkete... about a woman who sued a company and won, because of multiple robocalls that she got from this company. I think it's worth a try.