This is so much harder than it should be. Since making this video, I've seen the same system in use at Fairfield by Marriott and Autograph Collection Hotels, also by Marriott. This method will work there, as well, although the volume issue I describe here is not always the case for every TV. It seems some hotels make using the HDMI inputs on the back of the "cable box" much easier, but as you see in this video, that was not the case in this instance.
00:00 Introduction
01:41 Instructions
02:17 Volume warning