Hi Tim,
If I give the submitter (originator) only read rights to the SharePoint form library - there is no "New" action and the user can't start the form - to get the new button the user needs to have contribute rights.
With contribute rights the user is able to delete the "temporary form" - and the destinator of the next InfoPath Client Event can't work with his notification mail (link to the form to approve for example) because the form is away.
Your trick works - but unfortunately we like to use the InfoPath Form Services.
I'm sure that in the training labs the examples works with browser forms - and the forms seems to be not in the library or "hidden". Why isn't this possible now - I can't understand the differences.