In principle the mac can be used to identify a tablet when it connects to an access point(*) and it can currently be used to download the fiasco images from Nokia's site.
Since the mac address can be easily changed, it's not that effective for identification purposes, and a tablet owner can already download the fiasco image.

(*)the hack only changes it as seen by navicore, but nothing stops anybody from using the mac for other purposes once they know it. Most home routers won't keep a long term log of connected MACs, but some public access points do.