As you are aware - wearing a mask is primarily for you to help contain your covid 19 laced droplets within your mustache - and not so much to protect you from the covid 19 droplets of others.
If your countryman is wearing a mask as well, both of you are better protected. Best? No, but better - & that seems to be too much for some (mainly N. Americans - by the figures) to deal with.
When you drive an M-1 tank you don't have to stop at Stop signs, but it is a thoughtful thing to do.....
Like that....goes the thinking.
Agreed - sad that thoughtfulness has to be mandated for some.
Stig