Apparently the FAA has decided that cordless mice with their nanowatts of transmit power represent a risk to airplanes. Discussion forums contemplate that the FAA is concerned they could be used to trigger explosives in the hold (when they outlaw cordless mice, only outlaws will have cordless mice). Perhaps they found a cordless mouse that used a spark gap transmitter and so banned the whole class.
BTW, this is being posted via gogo inflight, the wireless radio on my laptop also uses 2.4ghz unregulated and could be 200mw and who knows who made it (same frequency band, 3 or 4 orders of magnitude more RF power).
While I’ve dealt with worse, I am on occasion reminded of just how awesome the air bureaucracy in this country really is.