[Fury]

This is likely what is happening in hospitals where nurses and doctors are getting sick with Covid-19. They are not changing out the mask regularly probably due to lack of supply.

It's also possible that they are bringing hand to mouth or nose inadvertently after adjusting or moving the mask up to eat, drink, etc.

As written before, unused masks (even expired), can serve a purpose to help deter people from bringing hands to mouth and nose. They also have the psychological effect of making other people aware of a mask wearer, which will probably result in people not wanting to be in close proximity to a mask wearer. But people need to be aware of the limitations and practice good hygiene regardless.

[21twelve]

I'm guessing that our medical system still has the protocol in effect that the mask is tossed after each visit.

I hope they quickly take the Chinese method. Suit up for 8 hours at a time. Use an adult diaper.