[development] custom options passed to url()

I have a module which implements custom_url_rewrite_outbound() (in D7, will implement hook_url_outbound_alter()). A user of my module has requested a change; that I honor a special option which changes the behavior of my url alter. For details see http://drupal.org/node/931660. So to be clear, this would be a new option passed in the $option array to Drupal's url() and l() functions. An option not documented on api.drupal.org, but passed through and honored by my module. I actually like the proposed patch, and want to include it in the module. I just wanted to ask here first: does anyone see a problem with me using the url $options this way? Do any other modules do this? Thanks, -Dave