We could do with a lot of these up all over our campus. I'm not convinced many people will understand what to 'expectorate promiscuously' means. It could be put more bluntly. 'Don't violently or frequently sneeze your snot and germs around and about'.
Or some such.
The science of sneezing courtesy of MIT
> The distance germs can travel
One powerful sneeze, unhindered, will fill a room.
> Allergies, sinus infections and sneezing ...
> Sneeze Reflex : Facts and Fiction