I don't personally see a issue with using LOOC to say a joke/shitpost/talk about something outside of the round while nothing is happening. Restricting it mechanically or rulewise isn't going to solve anything other then make rounds slower/more quiet. If you don't want to hear it you're also free to mute it, same as OOC.
Also, if ghosts abuse it to say something they shouldn't then they are bwoinked. This rarely happens, restricting it completely from them isn't really needed.