On meddling with user configurations

[Henrik Nilsen Omma]

So we have a general principle that we shouldn't meddle with user 
configurations during updates and release upgrades, which on the whole 
seems sensible. Is this policy written up in some detail somewhere?

Does the policy distinguish between new and existing user accounts? I 
guess the general principle is that we can set new defaults for new 
releases, but if the user has already changed the default settings then 
we should not change them back.

My question is: to what extent does this policy restrict us from doing 
cool things for new users? I'm coming at this from the example-content 
perspective:

We are including some example sound files, OOo documents, etc. in 
dapper, intended to help new users explore the features of the different 
programs. IMO it would be helpful to have the sample music clip show up 
in the Rhythmbox library of a new user account. New wallpapers should be 
already added to the wallpaper selector and Office documents should be 
added to a folder in the users home directory.

None of this is useful for existing users though, so IMO we should just 
skip these changes for existing accounts. If you already have your own 
collection of files, wallpapers, bookmarks, etc, then you don't need 
this example stuff. It is, however, very useful for people who are just 
checking out Ubuntu, perhaps on a live CD. If they quickly discover some 
cool stuff they can play with they might be won over.

So, are we able to distinguish between these two situations and make 
these changes only for new users?

- Henrik