As stated in the article, the previous version of the network required MAC addresses for authentication, and you can easily code something that will allow you to add a MAC to your account from a Web page.
But they wanted to do something new, where you don't have to ask students for something quite obscure for non-techs such as MAC address.
Of course the biggest caveat here is the number of VLANs (4096) that limit the scalability, but which was satisfactory in their case.
I think you misunderstood. In what I'm envisioning users would not need to type in a MAC address. The infrastructure would detect the new device (via MAC and/or other fingerprintable characteristics) and tie it to the user based on time (here are devices plugged in recently), location (filter by devices in jacks or access points we think are assigned to / proximate to you), and their input (yeah that guy is mine!). You could have them disconnect/connect the device a small, specific # of times to confirm, if there's too much ambiguity (lots of similar new devices just plugged in).
But they wanted to do something new, where you don't have to ask students for something quite obscure for non-techs such as MAC address.
Of course the biggest caveat here is the number of VLANs (4096) that limit the scalability, but which was satisfactory in their case.