Notify users when changing user privacy/leaving profile edit without save
In conjunction with profile visibility fields, it was noted that field visibility can be modified, and the slider can be closed, without the text having been saved, and it's conjectured that this could cause confusion for users who may not know to save their changes. See http://redmine.gc.cuny.edu/issues/120#note-20 for extended discussion.
The suggested solution is to prompt the user before leaving the profile edit page without saving, if they have made changes. See how WP warns you if you attempt to leave the blog edit page without saving.
Putting into 1.5 for the moment. If we get feedback that this is confusing, we'll consider moving it to a bugfix release. Dom, you're getting this one - I encourage you to see how WP does it (I think there's actually a browser standard for doing this, as I see similar notifications across even non-WP websites).