The Spectrum uses 2 of the 80 avialable 2.4GHz channels simultaniously. And cant use any of the others in use by other RX/TX recievers. Also, wont interfere with the other systems on 2.4 GHz.

The Spectrums at least, with the BR6000 has therefor 40 frequencies at its disposal. In effect far superceding tthe mandatory 3 sets for other frequencies.

But yes, even if the rules arent blatantly on the FRA forum, the Spectrums are accepted by the event organisers (who, after all are more important)