Ofcom, the UK regulator, has deigned to allow UK citizens license-exempt use of the 275-3000 GHz band. These are freqencies have historically been lumped in with Infrared. Of course, these are temporary regulations while they await an international decision at the World Radio Conference in 2011 (WRC-2011). So it's not just Ofcom that troubles me, but spectrum regulator's in general. Best bets are, after 2011, everyone will be regulating 275-3000 GHz, but why jump the gun? As for light, there will also be a discussion at WRC-2011 about regulating "free-space optical" communication. At least the US is on record as opposed to regulating free-space optical links.
Over the decades, government regulators have gradually expanded the range of frequencies they consider to be the radio spectrum subject to their regulation. But until recently the highest frequency that anyone considered "radio" has been 300 GHz. See for example this excerpt from a US Department of Commerce chart in 2003 (full chart here).
Very little use has been made of any spectrum above 60 GHz although there are commercial products in development in various bands between 60 GHz and 100 GHz. The problem is, at higher and higher frequencies, absorption due to oxygen molecules and water vapor increases until you reach a "window" that we know as the visible light portion of the spectrum. Since the atmosphere contains oxygen, not to mention water vapor (yes, even in desert areas), transmissions above 300 GHz are severely attenuated.
So whatever happened to the principal that you leave things unregulated until and unless it becomes clear that regulation is required?