Any way to Lock the In Playback Video Settings?

The situation is this: i made a decent set up for kodi on the living room TV, Living room TV is dominated by my brother in law and his Children. I showed them how to use kodi with a 360 Controller, they love it. The only problem is that my brother has figured out how to adjust the pixel ratio from the video settings during video playback. This causes me to constantly cringe. I give them movies in 1080p HD to watch, but he goes and adds Black Bars to everything, Claiming “You can see it better that way” V.v – To me this is folly, there is no need for any black bars on anything in my opinion, the reason we grew up watching things with black bars on them is that we had SQUARE CRT tvs as children, and Movies are / were shot in Rectangles. Now we all have HDTVs which are in the shape of RECTANGLES, and Movies are all still shot in RECTANGLES, so there is no reason to watch any movies in black bars, KODI even has a setting to Reduce Black Bars, because devs know how much we hate black bars….

So what im trying to do is lock him out of the in playback video settings so that the pixel ratio will remain the way i have it set and set to default. He is the only one in the house who wants black bars on all his movies, even the children dislike it and agree with me that we shouldn’t be watching anything with black bars.is there an XML i can edit and Lock down somehow to prevent him from making any changes? the Profile Lock settings don’t seem to affect it.

This is on Kodi 16.1 Jarvis BTW, i dislike Krypton for my own reasons.

Any solutions appreciated!