From the instruction card by the phone in my room at the JW Marriott Hotel & Conference Center somewhere outside Las Vegas (which does not offer wireless internet):
All persons wishing to use the high speed Internet service are required to have a functional Ethernet card installed on their computers as well as a Category 5 Ethernet cable at least one meter in length.
Indeed. It would be irresponsible and immoral to do otherwise.
Who writes this stuff?
The JW Marriott Hotel & Conference Center also offers dial-up, by the way, in case you need that. Same deal, must have modem, no short cables.