Is it really possible to know it's unused out in the wild?

Probably not.

The method right now contains an undefined variable which will produce a warning on every page call.
So that someone out there in the wild must have his/her error_reporting pretty low ;)

Thanks for your contribution - At this time we are only using github as the place to submit code fixes, the actual reporting of issues and testing fixes is still taking place on Joomlacode.

As it has been some time since you opened this issue can you please confirm that it is still valid with the current Master or Joomla 3.2 beta. If it is no longer valid then please can you close this issue. Otherwise please can you:

1) Open an item on the Joomlacode tracker in the appropriate area.

CMS Bug Reports: http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemBrowse&tracker_id=8103

CMS Feature Requests: http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemBrowse&tracker_id=8549

2) After submitting the item to the Joomlacode tracker, add a link to the Joomlacode tracker item here and make sure that you add a link to this GitHub issue or pull request on the joomlacode tracker item.

No, it's not a valid issue..