After a very much needed long sleep, I wake up to discover that joeyh decided that another well known FAQ isn't what Debian really needs, so he put code to base-config that adds the first user to the plugdev group, if base-passwd added a static plugdev group.
Not long after, Kamion said this was acceptable and uploaded a new base passwd. When these two packages hit testing, the problem will be solved. Thanks to both!
In other news, I was a bit too optimistic on the amount of things that would hit testing last night. Unfortunately, a few missing s390 builds are also holding gnome-panel, gnome-applets and control-center, which I guess I can't call "minor bits" too easily. They will be in soon, hopefully today.