I have worked up some examples, with some great direction and help from Paul Guerette.
There are three forms.
The first looks at the different ways in sending out a form to users, highlighting what the user will be able to do with the form and what restrictions there will be (depending on whether it is enabled and how it was enabled). Thanks to dajknow for the LC Reader Extensions screenshot.
The third is a from that "tries" to show the sequence in which events fire as a user interacts with a form. Different objects (some standalone; some are bound by calculation script) are available in a test area. When you interact with these the counters will record the number of times the events fire. A log will show the sequence. The calculate and validate counters jump in sequence when the form is reset and I can't seem to get a handle on that, but apart from that I think it "reasonably" reflects what is happening.
I would appreciate any comments / suggestions / corrections that you have.
I have submitted the "forms in Acrobat and Reader" example onto the cookbook.
I am still working on the other two. I am trying to get the reset button to work properly on the events form. In relation to the form accessing Acrobat menu items, I want to make sure we catch all of the XFA equivalent commands before submitting.