3. If you get called, make sure the company's calling you is in the US before being a jerk and threatening them. While many centers are in the US here, many companies have centers in Canada doing the calling. They're exempt. As is anyone from outside the US.

IIRC, there was a court decision not too long ago that US companies contracting their call centers to firms outside the US are still required to abide by the DNC list, since the company being advertised for is still a US company. Can't find a google link, though.