I don't even get how this is government transparency. That's like saying everyone's cell phone records ("just the metadata") should be published, minus names, because telecom is regulated.
Government transparency is largely about opening the data they have available to them up to the public in a consumable way. FOIL requests like the one Whong filed are essentially the second-oldest way they have done this. (The oldest being, well, just asking directly.)
So, yes. It can definitely be argued that cell phone records, insofar as they are shared with the government in the first place, should be published. A simple counterargument would be that cellphones do not consume a public resource, unlike the way taxis consume road space, so there is no reason to share said data with the government and consequently the public.
But as a rule of thumb, government transparency is that any data the government has ultimately belongs to the public. It's not a matter of regulation.
>A simple counterargument would be that cellphones do not consume a public resource, unlike the way taxis consume road space, so there is no reason to share said data with the government and consequently the public.
That argument would be incorrect, since all cell phones run over a public resource: the airwaves. These airwaves are licensed by the FCC licenses to private companies, but (in theory at least) the public retains ownership of those airwaves.