They aren't readily switchable unless explicitly configured to be, and yes, I am speaking from direct experience.

I get your point, I am just saying that it is not universally true, even if my example is a stretched one (Cyrillic keyboard users always configure Latin-based layouts too, but it's not a default, and it's easy to forget esp if you install from a fully live env configured with both).

If it's still not clear, you can end up on a login screen with an ASCII password you can't type in, especially so without the GUI.