Hanging This From a Rearview Mirror Might Be Illegal Chances are good you have done this — or at least seen it — in recent months. Photo by Photographee.eu / Shutterstock.com A mask might keep you safe from the coronavirus, but it probably won’t protect you from getting a ticket in some states. It turns out that in some places, hanging anything from your rearview mirror — including a face mask — is against the law. That is because authorities in those states fear that hanging anything — from fuzzy dice to air fresheners, graduation tassels and, yes, face masks — might obstruct your vision.