Radio is a seperate code from chat and thats why "unknowns" are not on radio. But i believe that considering radio is one of the only fast IC ways of immediate communication long distance, and given the range of radios. I think that having unknown status brought to the radio would decrease the likelyhood of metagaming, be it unintentional subconsciously- or maliciously.
im sure the coding for this would be a nightmare, and thats why it hasnt happened yet. But i do believe that it is important to be added at some point in the near future. Maybe as an addition with the new update coming???