I’ve recently landed a change in Launchpad that allows members of the bug supervisor team for a product or distribution to modify the official bug tags for that object.
For Ubuntu this means that members of ubuntu-bugcontrol can now add and remove official bug tags. This is done by clicking the "Edit official tags" link at https://bugs.launchpad.net/ubuntu. The official bug tags are useful because they are suggested when someone is adding a new tag to a bug report and because they appear first in the list of bug tags on a bug report.
When managing the tags my thought process has always been that they should be tags people would add and not ones that are automatically added. This is why regression is an official tag and apport-crash is not. It also seems to me that the official tags should be usable on multiple packages.