Drupal 7 - civicrmtheme can't differentiate between public & admin pages if url aliasing is on

The args aquired by the civicrmtheme_custom_theme fn differ as follows

Clean URLs - alias on = civicrm/contribute/transact?reset=1&id=2
Clean URLs - alias off = civicrm/contribute/transact
Dirty URLs alias off = civicrm/contribute/transact
Dirty URLs alias on = civicrm/contribute/transact?reset=1&id=2

So, it seems to me we could simply truncate at the ? in the drupal civicrmtheme module before we start