This is not true and a myth! Illegal callers do not need to get the DNC which has to be paid for along with information proof of business.  The illegal callers use dialers and other methods such as computer and all they have to do is plumb in numbers from a to z..   The DNC can't protect you from illegal callers and is only aimed for telemarketers.

http://www.tcpalaw.com/
http://www.kleinmoynihan.com/publication/new- ... ctober-16-2013/
http://www.consumer.ftc.gov/articles/0108-national-do-not-call-registry
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https://www.donotcall.gov/
http://www.ftc.gov/opa/2008/04/dncfyi.shtm
http://business.ftc.gov/documents/bus27-complying-telemarketing-sales-rule
http://business.ftc.gov/documents/bus27-compl ... -rule#DNCrights