Attached to this email is the patch file that I mentioned
previously. This patch will allow you to select via the Captive
Portal config screen to only allow one user per login ID. Further
logins will kick the previous user out... (Which should be a good
enough reason to not share passwords, especially if you use VPN!)
This has been tested with local authentication. I believe it will
also work with Radius authentication, but haven't actually tested it
in that environment.