Re: CUA mode cursor color

[Richard Stallman]

    If you use define-minor-mode, then the resulting code emits
    a message if called interactively.  That should work for menubar
    invocation as well as for M-x without impacting direct calls
    from Lisp programs.

We could make that the convention and change all the toggles
to do it that way.

    I dislike the turn-on-X-mode things because they're just redundant.
    Luckily, they can be ignored.

One reason they are useful is that you can call them easily
from hooks.  In the context of a hook, you can't pass an argument.
To use the toggle, you'd have to wrap it in a lambda.