"On 4, should renaming or moving a file also require a tip? (an example of this: I would like to move the includes out of /www to /lib)."
So the guideline is it should be tipped if ... "it will change the behavior of any core package in a way that affects existing code (typically, by changing public API)"
I would opine that since there was no defined interface for includelets before /lib, includelets in /www are not part of a public interface. So you could rename them freely in www - I guess it's like a private API - but renaming or changing in /lib is TIPable.
On the other hand, we've made a bunch of changes to master template etc, just since 5.0, that it seems like overkill to TIP for. Maybe the rule for public includelets should be that changes operate on the "beg for forgiveness" model. That is, non-bugfix changes can happen without TIP, but only on HEAD, and authors must pay attention to the response.
