Well, even if you buy that story, it's still useless, because the law exempts:
- long-distance phone companies;
- banks and credit unions;
- insurance companies;
- all political organizations;
- all charities;
- anyone conducting a survey.
All those people are allowed to cold-call you even if you're on the list. Oh, and also anyone you've done business with in the last 18 months. (FAQ.)
I almost never get telemarketing calls, and my technique was:
- pay for anonymous call rejection;
- pay for an unlisted phone number;
- pay extra for an unpublished phone number;
- wait a year for it to propagate.
"Unlisted" just means "take me out of the paper book." "Unpublished" is what you need to get out of the databases they sell to spammers.