According to an article on CNN.com and other places, the FCC has fined Marriott $600,000 for doing what I suspect other properties have been doing also but not (yet) caught at.
According to CNN, Marriott, for reasons unknown, decided that they should be allowed to kill visitors Wi-Fi hot spots that were not connected to the hotel network at all.
Some people speculate this is because they want to sell you their Wi-Fi access. At the event in question, at a Marriott property in Nashville (Gaylord Opryland), the hotel was selling Wi-Fi access for $1,000 per device. I assume this was at a convention center event. Some admins speculate that they killed the personal Wi-Fi access points by masquerading as the user and sending DEAUTHs.
Marriott contends this is legal; the FCC has a different opinion. Marriott said they were merely “protecting” their customers and that they will try to convince the FCC to change their rules. They are required to file compliance plans every three months for three years and this covers all Marriott properties anywhere in the US.