Salvation Army
In Basel, Switzerland each year the good Protestant townspeople have a festival in which they all don masks and go through the city doing things and going placed they would never consider doing/going under normal circumstances. The mask, which veiled their identity emboldened them to do these things.
One year, the Salvation Army, concerned about the abandonment of moral standards, put up signs all over the city, which read, "God sees behind the mask.?