IMO, this happens a lot. A lady who works for me and is a multi-year GM didn't know how to request the upgrade online. She just thought because she was a GM that DL would wave the magic wand and transport her to FC automatically. After listening to her b!tching about being back in coach on flight after flight, I finally clued her in as to how to request the upgrades online.
Thanks to folks like her, however, those of us who are savvy to this process get upgraded more often. We don't really need EVERYBODY knowing the process to upgrade....