<blockquote> I would really like to make ad_page_contract work with
includeable templates, which wouldn't be terribly hard,
we'll just have to make it look in the caller's scope
instead of in the page form.
</blockquote>
ad_page_contract does work in includeable templates to the extent that it looks in the form data of whatever page it was included from.
I don't know of any included templates that actually use ad_page_contract this way, but perhaps someone out there actually relies on this default behavior. Can anyone make a case for retaining this behavior?
If not, then I agree with your suggestion. (Though it does seem a bit strange having the same command do different things depending on the context.)