I'm in the UK: won't wear a mask but got a lanyard with an exemption card. Not been challenged but had people say they wish they could get one too, so I tell them how. One woman freaked out because I got too close. I asked what the problem was if her mask worked? She freaked out more because she had not (or could not) engage brain, called me selfish and irresponsible. Now I tell people masks are as useful as a knitted condom. Most laugh and agree, some get angry. Fear porn is a very powerful weapon.