Hack Idea?

Within the spectator view, there is the capability to display lines in which indicate were a player is looking, so with this is it possible to develop a hack in which you can toggle this on and off in a real game. So having access to what ever makes the line displays functions, implemented into a hack to be used in for say competitive match. In which could replace walls to know where one is looking?

Yeah this could be made, but do people wanna make it.