Facinsating, although I empathize. I assume peaceful resistance of politely reiterating the reason is private would require them to yield eventually? If not, seems like it’d make for a great audio clip for some morning news show.

It's likely on a per-callcentre and per-agent basis.

Remember the agent is often required to record your disposition at the end of every contact, they can face consequences if they misuse buttons like "Answering Machine" and "Hang Up". So if they get ahold of you, they really want to get a reason out of you.