Given the lack of information from BIS, there are two possibilities:
1) Naturalpoint have blocked older versions of trackIR and other headtracking from using the trackIR API, but have not prevented BIS from implementing others: in which case it is a very simple matter for BIS to add freetrack support into the next patch, and just requires more public pressure for them to do so.
2) Naturalpoint have blocked older versions of trackIR and other headtracking from using the trackIR API, AND have tried to create a monopoly by (illegally) preventing BIS from supporting other headtrackers.
In which case I recommend all EU citizens affected to report this to the Antitrust commission:
http://ec.europa.eu/competition/contacts/antitrust_mail.html
and in the US to the relevant authorities.