Of course I have no idea about the real capabilities of that 6GHz equipment to use different bands in case of interference, that is most probably classified info. But economically, it would be silly to have all military equipment in continental U.S. work nominally on many different frequency bands. Likelihood of effective jamming of 6GHz bands in the U.S. is quite small (island with large area far away from enemies, low effective range of 6GHz radiation). Some systems have to be resilient against radio interference, such as attack warning systems or government - military com systems, but there is lot more in military - support systems, test systems, research systems, training systems and god knows what else.