If we didn't allow for an exemption but still required full compliance, perhaps manufacturers could physically limit the output from the power amplifiers and/or use blowable fuses in the chips to set a non-modifiable power limit. I imagine that the same could be done for frequency management either on board (bandstop filtering) or on chip (once again, blowable fuses to set disallowed frequencies).

I know that there will still be enterprising folks who modify their hardware itself to try to get around these limitations, but such enterprising people are already more than capable of physically modifying their existing hardware.