When I bought my Glo, I created a brand-new Kobo account for device registration only and have never bought anything on it. After registering the device, you can delete the Kobo app from your desktop and/or turn off wireless. You can turn off the social networking features. I remove DRM before side-loading, so I don't have the device registered with ADE. The only thing I do need to do this is a computer.
I have never experienced any of the firmware bugs mentioned by Danger.
A Sony T2 would behave in a similar manner as the Kobo, I believe. I seem to recall needing to register my T1 device with the Sony desktop initially, but maybe that has changed.