As the FCC explains, the hotel was effectively asking users to either pay twice for internet access or else risk going offline whenever they approached the convention center. For its part, Marriott insists to Recode that this WiFi jamming was legal, and that it was simply sheltering guests from "rogue wireless hotspots" that could slow down service and open its network to attack.
However, the FCC doesn't buy that claim -- it contends that personal cellular routers "did not pose a threat" to the hotel or its guests. No matter what the motives, the settlement suggests that you won't have to worry about going incommunicado the next time you're on a business trip.