NUL was often sent as padding to slow (printing) terminals. Although that was just before my time.

Maybe 32 was a bit much, but even fitting a useful set of control characters into, say, 16, would be tricky for me. For example, ^S and ^Q are still useful when text is scrolling by too fast.

Back in early times, I used to type ctrl-M in some situations because it could be easier to reach than the return key, depending on what I was typing.

Its inscrutable undo and redo behaviour is probably the main reason why I never really tried to get further into Emacs. And that's when I had just access to original vi, not vim.

My bank's app uses Google Pay to pay at POS terminals, so Google can at least block that.

Very privacy sensitive? In Germany, maybe. Elsewhere in Europe, not so much. See the regular attempts to push through something like chat control.

PTT = push to talk (at least that seems the most probable match on Wikipedia)

I think a black bar is in order.

Amen.

is there a list somewhere of people that did cause a black bar?

For the average non-schooled singer there is a lot of new information here. I have sung most of my life, in choirs, in church, and otherwise (not much in the shower though), and don't explicitly know most of these things. I have heard there are things like chest and head voice but I wouldn't know where one ends and the other begins.