Madcaps.   Worn in nuthouses to reduce incidents of head lice.   Bonnets of all sorts have been worn to keep grime out and one's privacy within.   Superstitions such as never letting anyone leave their dirty, grimy hat on a bed.  It is bad luck to leave a hat on a bed.   It goes to lice infestations.  Some cowboy asswipe throws his ten gallon hat on the bed, it could give everyone in the flop house a case of vermin.  People need to wear a hat.