What good does it do? If legal telemarketers (there are still a few, I think)  see your number is on the list, they won't call you. Unfortunately, DNC doesn't apply to everyone legal (surveyors, politicians, charities) and the illegal aren't concerned about violating it.  And the surveyors, politicians, charities, and criminals outnumber the legals by a large (and growing larger by the day) margin.  A HUGE margin.
In short, there is NOTHING that can prevent someone from calling you on the telephone, provided they have your number. There are lots of things you can do after the fact (block calls, refuse to answer, report to DNC & local law enforcement where applicable, etc.), but unless you want to ditch your phones (cell and land line), you will continue to get calls. Gen. MacArthur said only the dead have seen the end of war, and I'm afraid only the dead have seen the end of nuisance telephone calls.