If not for frauds abusing the phone networks, we would never have a DNCR, therefore the Registry also applies to the scofflaws. It's fair to say that crooks make a choice to ignore all pre-existing opt-out registries. When Federal lawsuits catch up with bad actors, they learn the hard way what "applies" to them.
Anyway, it is not yet clear in this thread that we have a sales caller at issue, without which all the arm-waving about DNCR compliance is a waste of energy.