> Most countries have these no call lists but they are fairly useless as there is no enforcement

What country are you in that it doesn't work in? I know for a fact it works in Spain and Sweden, but it'll really depend on the country. You'd help by others by being a bit more explicit :)

> I've even heard stories of some scammers exclusively using such lists, as they are pre-verified!

That does suck and seems counter-productive indeed! Even more curious what exact country you're talking about now.