As much as I dislike Mariott's practice here, this is clearly outside the scope of the FCC's regulatory powers and as far as I know isn't even in violation of their own regulations. First of all, WiFi operates on UNREGULATED spectrum, which means anyone can use, and anyone must accept interference from other users.
Not quite true, the ISM bands are Unlicensed bands, not unregulated. In order to sell equipment used to transmit on these bands, the systems must be type approved. Part of this type approval process includes ensuring that the equipment in question will not cause undue interference to other users on the band. To me, sending rogue de-auth packets constitutes interference.
In Meraki's Air Marshal Whitepaper, they explicitly state on page 8 that Unauthorized containment is prosecutable by law (subject to the FCC’s Communications Act of 1934, Section 333, ‘Willful or Malicious Interference’)..
I actually had this particular issue affect me. As a volunteer, I operate a community-wide network, including a widespread wifi network, at a retreat centre high in the mountains of WA. At this time, there is a significant mine remediation project going on in our valley, so we have leased out several buildings to the construction companies, who setup their own Meraki system. Unfortunately, they enabled Air Marshal, which then went on to attack our wireless network. Despite running WPA-Enterprise on our network, it was still successful in attacking our networks, and rendering them nearly useless. In the end, we had to flex our muscles as the landlord to get the feature disabled.
In my mind, the ability to attack adjacent networks should be illegal, and Cisco and the others should not be permitted to sell this technology to the general public. Rather the systems should simply alert on the presence of other wifi networks, and assist in locating them. Also, the wifi standards should really be updated to fix this type of vulnerability... in a WPA-Enterprise environment, clients should only respond to a de-auth packet encrypted/signed with the session key between the client and the AP its connected to.