Canonical method for avoiding HTML expansion?

[Lloyd Zusman <ljz@asfast.com>]

I recently asked something similar to this, but I can't find a
response that specifically addresses this question.  Forgive me if I
missed the appropriate reply ...

I'm using the latest CVS version of Gnus, and I have the following
assignment in my `.gnus.el' ...
 
  (setq mm-discouraged-alternatives 
        '("text/html" 
          "text/richtext")) 

Up until recently (within the last few weeks), this seemed to properly
prevent expansion of HTML when it appears within email and posts.
However, lately Gnus has been expanding the HTML to the max, including
automatic attempts to download images and the like, and it's a real
pain to try to abort this once it begins.

I was told here that the `mm-discouraged-alternatives' variable
controls cases where there is both text and HTML in a message.  I'm
not sure if this is still working the way it's supposed to, but even
if so, there apparently is enough non-perfectly-compliantly-MIME-ized
HTML junk coming to me so that `mm-discouraged-alternatives' gets
frequently ignored.

In any case, I'd like to be able to prevent the automatic expansion of
*all* HTML and only have that done on demand.  Clearly Gnus is able to
determine when there is HTML (or else it wouldn't know to try to
automatically expand it), and so the processing that I'd like to have
happen would go something like this:

(1)  Gnus somehow determines that there is HTML that could be expanded.

(2)  The normal HTML-expansion code gets bypassed and the portion of
     the message that could be expanded gets processed in one of the
     following ways (in order of preference):

     A.  It gets hidden and buttonized so that I would only see
         it if I specifically select the button.

     B.  A quick-and-dirty HTML-tag-removal is done as part of
         something akin to article treatment.

     C.  The HTML just shows up intact as text, with all the tags
         appearing "as is" within the message.

I know that all of these are at least theoretically do-able, but what
I'm looking for are the canonical methods for accomplishing one or
more of these.

A related question is this: within which hook(s) could I put my own
code in order to prevent and intercept the normal HTML expansion?

Thanks in advance.

-- 
 Lloyd Zusman
 ljz@asfast.com