I don't have direct knowledges of practices of companies who refuse to disclose who they are. What I'm saying comes from the fact that it just hasn't worked for the calls to my line. I switched numbers to make them stop. There's an Internet full of reports of other people saying the strategy you advocate doesn't work for them either, and the government agency that regulates the phone lines explicitly recommends against it.

But we could call that dueling supicions if you'd like.

And just to clarify, you're talking about a US number that's been listed on the national Do Not Call list, right?

And not just regular scam calls, but calls placed by an automatic dialer and answered by an automated system that falls to a human caller only after being answered, right?