Hotels are out there to make money off you. Once they have you paying for a room, one of the sweetest plumbs of upsells is the television entertainment. Who doesn't like lounging around in the room watching television? And who wouldn't like to veg out by watching some movies? Hotels are notorious for charging exorbitant amounts of money for customers to rent a movie through their pay per view system. They don't want the customer to be able to play their own movies on the hotel TV because that would undermine one of their most lucrative revenue streams. So, most hotels lock out the extra video inputs via a small device mounted to the back of the TV.
So, you want to play your own movies on a hotel TV but the input selection function is locked out? All you have to do is look at the back of the TV. Do you see a box mounted on it with a phone line coming out of it? Yank out the phone line that is going from the box into the television. This should give you access to change the input on the hotel TV (make sure to put the phone cord back in before you check out. Just in case). From there, you can easily play movies from any device that uses HDMI input. While you may be able to access the USB display input, you may not be able to play movies via the USB interface. Many hotels lock that out via the Firmware. In order to get a USB display interface working on a hotel TV, you would have to look up the television model and then download the latest firmware for it and install it onto the TV.