Join Date: Dec 2008
Location: Mostly living in the basement
Programs: Free Agent Level 2; MR LT(!)TE, HH SE, ALL SE, BAC Silver, DL MM, UA PS, 2V Fanboi, CBP GE
Posts: 5,347
This is interesting, and definitely a reproducible bug. The "Book a Trip" link on the main page only shows the "Request Upgrade" button when logging in with SM #. This is for the search box on the front page.
The advanced search page shows the check box regardless of how I log in.
And FWIW, my email address is not connected to any non-Medallion accounts, so definitely a bug in the web site.