Needs some big improvements from New Vegas, but the idea is solid. I can't recall the name, but there were games that only personnel like officers could see through the disguises. I think the effectiveness should tie into the faction rating, number of officers and sneak skill.
As your hate with a faction increases, then they'll likely know you better, perhaps have a wanted poster. So disguises lose their effectiveness. Additionally, the use of the disguise would rely on character's skill in sneaking.
This works in reverse as well, meaning that if you're idolized by a faction, they will likely realize that despite being in enemy attire, they will not shoot.