Thanks for that! I tried logging in and navigating to the page, but kept getting errors at the "Privacy & Notifications" page (maybe because I'm on an old pre-paid plan?). That direct link worked fine, though. (Though who knows if it will actually take effect, or mysteriously lose my preferences.)

There should, and I realize this is a bit pitchfork-EY, a limit on number of clicks to find one of these opt outs.

Agreed. Even with the nicely supplied shortcut URL it was still 16 clicks for me to turn everything off for 4 lines.