[mvilim]

  | However, I've been toying around with the idea
  | of eventually writing a minimal 'vi' clone that
  | you cannot exit. I'm sure there's pent-up demand
  | just waiting for one!

If a user space program can be truly unexitable without restarting (including the possibility of killing it through another shell, of course), then would you consider it to be a bug in the operating system? Seems a reasonable conclusion to me.

[cjfd]

I once played a maze game on X where the maze would literally not allow the mouse cursor to go through the walls so it would be taken hostage. The only way to continue your X session was to solve the maze. That was quite funny. Oh, well, there could have been some other keys that would have done something about it but it was fun anyway.

[stefco_]

It would indeed be a bug, which is why any self-respecting operating system should include uninterruptible vi in the kernel /s

[dbtx]

Alt+SysRq+k

(read linux/Documentation/admin-guide/sysrq.rst before you try this)