At least in my opinion it would add a lot of value to be able to track the users gaze. With that we could set it up, so that censoring increases if the user watches forbidden categories (gaze position/direction matches or is close to the position/area of the category).
Even better if a software tracker could be used that supports normal webcams or smartphone cameras as webcam instead of expensive hardware tracker. There are open source libraries/projects available that offer something in this area. For example:
https://github.com/NativeSensors/EyeGestures