I don't know that the presence of a query string is a great indicator of whether the link causes state change (cue the typical GET immutability arguments, etc.)

I don't know that the presence of a query string is a great indicator of whether the link causes state change (cue the typical GET immutability arguments, etc.). For example, in Drupal every path (whether or not it causes state change) has 2 forms: "/?q=path/to/page" (when you don't have access to .htaccess or .conf) and "/path/to/page" (when you do, and you enable clean URLs).