lucy24 - 10:49 am on Nov 16, 2012 (gmt 0)
but I think the page has to be authorative in the first place
Uhm.. uh.. I don't think so. I've had jump-to's ;) Not a whole lot of 'em mind you, but now and then. And usually they're very sensible.
Wikipedia's article sections are perfectly ordinary fragment links identified by <id = "blahblah">. (I thought they must be, but just sneaked a look* to be sure.)
* Browser history offered up Hall Beach, Albert Lord, and Frederick Hale. Only one of the three was long enough to have subheadings.