Re: Delegating user-reserved key binding space definition to users

[Phil Sainty]

AFAIK...

You can't arbitrarily prevent key sequences from being bound in
keymaps, because you can't control how or when that happens.

You can't control when it happens because that time might be "before
you started (or even installed) Emacs".  Keymaps are sometimes
generated at byte-compilation time, and thus even if you were to take
the extreme measure of preventing define-key from doing anything at
all, you will still acquire populated keymaps when certain libraries
are loaded (although if the libraries were byte-compiled while the
neutralised define-key was in place, you would then typically be
loading empty keymaps; but you would need to recompile everything to
get to that point; and of course most installations of Emacs will
include pre-compiled .elc files).

Native compilation might preclude even that, as IIRC it compiles
everything asynchronously in isolation, so the intended clobbering
of define-key might not actually be in effect when the native code
was being generated.  You would then have to edit the core code to
enforce your override irrespective of whether your custom code was
loaded.

You can't control how it happens because libraries can set bindings
without using define-key.  In the simplest case `use-local-map' for
one of the aforementioned pre-generated keymaps may easily occur; but
also a keymap is, after all, just a list, so it can be manipulated in
any number of ways.

(In practice I think that messing with define-key and recompiling All
Of The Things would affect almost all keymaps; but in general there's
no guarantee.)

I would suggest that your best option is to instead ensure that the
key lookup sequence always finds your preferred bindings.  Despite
your concerns about that approach, it seems more viable to me.