Well, perhaps it might be possible to catch some tummy bug from someone else, I don’t know, but you inhale the fecal particles when you flush anyway I suppose.
The lid stays down all the time (well, in between use) at our house, with the idea that you minimise the amount of fecal particles floating around your room. I know it doesn’t eliminate it, but I want to flush as much as possible of the poo and not inhale it, so I insist on the lid being closed.
I’m not claiming danger, I just don’t like the thought.
At first I read that as an old printer from a school, and thought that was a very weird thing to want, but then I realised you meant a printer that was old school, and it all suddenly made sense to me!