Having to take your metal armor off to sleep doesn't have to be optional.
Being ambushed in the night is a valid tactical element that lets Monks, Rogues and other lightly armored characters have a situational edge over characters who rely on heavy armor.
And it's just another immersion issue. Knights don't wear plate armor 24/7. It's not comfortable. You would want to take it off as much as you can.
I would say keep your immersion, but dont screw with mine. :-/
If my Dwarf refuse to take off his armor, who are you to comand him? :P
