Sorry, just to add a thought: I said "where script tags should go".. I didn't mean that... I actually meant whether script tags are included in an MXML class or not.
Now that I think about it, it might be nice to have the layout of a document to be consistent (sorry if this is tangential to the original topic, but it seems to have gotten here), such that maybe a script tag (if it were to exist) should be in a particular order (i.e., after the layout tag, and before children declarations, etc).