[trogggy]

Simple solution but from the sounds of it this Pi has multiple keyboards and mice connected. But you can get USB toggle devices basically a switch that will disconnect the connection in the middle. You could use that with a hub to kill every keyboard or mouse going through it and switch it back on when done playback?

The problem with that is anyone can disconnect the switch or hub and plug in their own keyboards. I want to prevent anyone else from controlling the system during video playback by blocking keyboard functions or physical access to the USB ports.

We're at post 14 by the time you think to mention you're worried about people plugging their own keyboards in?

Buy a lockable cash box. Drill holes for dongle (remote / keyboard / whatever), power, HDMI, ethernet.
Place pi in box.
Lock box.
Done.

[DJ_Izumi]

The problem with that is anyone can disconnect the switch or hub and plug in their own keyboards.

I am surprised to hear that the behavior you described in your previous post would occur in the professional "Commissioners Office" environment where Kodi is located

Yeah, this is starting to sound more like Kodi playback for a daycare classroom or something. o.O

Why do these people even HAVE keyboards if we're afraid that they'll plug in their OWN keyboards separate from any other peripherals? I mean, I GET if it's a system where everyone at times can make input but you don't want fidgety hands moving their mouse cursor or something but beyond that I don't see why adults aren't just being told 'STOP TOUCHING THAT'.