Yes, it has been discussed before. Frequently. I think that it is likely to put sufficient strain on the system that you would find most people turning them off.
And unless you want everyone to look identical you will need to model a large number of different people, wearing different clothes/ uniforms... I think that would be a lot of development work for a feature that most people would turn off!
But have a closer look- there are some people on decks in missions.
Stu