I've always been concerned about the matter of placing the same mask on various persons from act to act. How sanitary can that be? I know the conscientious vent will sanitize the mask between each and every use, but how does the audience volunteer know (unless prearranged). I can promise you if I was unexpectedly called up as an assistant during this worse that usual flu season, and the vent produced a mask for me to put over my face, I'd find a way to tactfully refuse. Maybe it's just me?