$_REQUEST[q] vs $_GET[q]

I need to make purl work with geoip_language inside the geoip api which also checks and potentially modifies $_GET[q] at the beginning of every page request.

There should be no issue to make sure geoip language runs before purl so that PURL gets q with the language already stripped out of it. However PURL uses q from $_REQUEST instead of q from $_GET. This patch changes PURL to use $_GET[q] instead in order to play nicer with other modules that modify q.

I can't see where or why it should use $_REQUEST[q] over $_GET[q] since core drupal as well as geoip language only look at and modify $_GET[q]. If there is a good valid reason for doing so then this patch may not be appropriate, but it looks like it should be perfectly safe in doing so.