Well, the beard masks are translucent polypropylene or some such, a mesh that you can see through and which which wouldn't restrict breathing at all if you pulled one up over your nose and mouth. But I would bet money it would set off the "Karen Alarms" because it doesn't look like they want you to look. I guess you could get into an argument about whether polypro is an approved material or not, and it wouldn't do as much to stop a sneeze.
I probably won't bother to test the limits but it would be funny if someone did. "You say I have to wear a mask. I AM wearing a mask!"
If somebody actually presses that mask thing I've always got a bandanna in my back pocket. Takes a second or two to put 'er on and pro-cede in full cowboy-in-the-dust mode.
Don't know about the tourist towns, but haven't seen more than 1-in-10 people wearing masks around here and only some of the Big Boxes/National stores making their staff wear 'em. (Or approximations or bandannas or hangin' off their ear or...)
Don't call Montana the "Don't Mess with Me" state for nothin'. Entirely too many stubborn SOB's around....