RE: customize-apropos

["Drew Adams" <drew.adams@oracle.com>]

      This message is shown if someone does `C-u M-x
      customize-apropos' - that's what we're discussing, right?

    Yes.  Actually, it is shown in four situations:

    1. As a result of a bug in some code.  (This is by far the most likely
       situation)

    2. If somebody uses C-M-c in the minibuffer (RET or C-j will not work)
       to get around the minibuffer completion functions which are
       designed to prevent such variables from being shown in a Custom
       buffer, unless the user is savvy enough to know how to override
       these completion functions.

    3. If the user calls M-x customize-variable or friends from Lisp
       instead of interactively, again in an attempt to override the
       completion functions.

    4. If somebody uses an obscure numeric arg, meant for expert users, to
       customize-apropos.

    These are all marginal situations.  We are talking about some very
    marginal aspect of Custom here, that is only going to be used
    _intentionally_ by experts.

Using a documented `C-u' with a standard command is not some bizarre expert
behavior. If this is not intended for users, then let's get rid of the `C-u'
option. I vote to keep it and clarify the Custom-buffer messages
accordingly, but if people think this `C-u' behavior is something for
experts only, then let's get rid of it.

The other cases might well correspond to a message such as you have
provided. It's unfortunate to lump together a message that responds to
obscure bugs ("the most likely situation") with a message that responds to a
user's `C-u'.