Just to confirm that it was a release, but 2.7.1 so not the current. Doesn't appear to happen in Python 2.7 (as shipped with Fedora Core 14) or in Python 2.7.2.
C:\>\Python27\python.exe
Python 2.7.1 (r271:86832, Nov 27 2010, 17:19:03) [MSC v.1500 64 bit (AMD64)] on
win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import urllib2
>>> urllib2.Request("http://host/path#fragment").get_full_url()
'http://host/path'
>>>
Upgrading our affected Windows boxes to Python 2.7.2 seems to solve the problem.
We're happy for this bug to remain closed.