"At present customers receive an SMS asking them if they're OK with the idea, and if they don’t say no then the third party (in this case the airport) gains access to instant information about the location of the phone, and hence that of the user."
Er, no. Make it opt in or the phone gets turned off. That's if I even get as far as the hellish Prison / Shopping Centres hybrids (good analogy btw, El Reg).
So on the one had we're suggesting people should check in by mobile phone, but on the other, we're being told that airports are to be the front line of the id card implenentation.
Quite apart from the failed history of "your mobile will be able to do XYZ" ventures, what's the betting that it'd be a half arsed measure anyway. A la swish and handy credit-card sized photo driving licenses that are only valid when acompanied by a sheet of A4 that couldn't possibly be faked. Because forging a text-only paper counterpart is a real dog once I've faked a laminated, watermarked, photocard.