“ Appellant Palmer was convicted by a jury of violating the City of Euclid's 'suspicious person ordinance,' that is, of being
' (a) ny person who wanders about the streets or other public ways or who is found abroad at late or unusual hours in the night without any visible or lawful business and who does not give satisfactory account of himself.'
He was fined $50 and sentenced to 30 days in jail. ”

“ A female left his car and entered by the front door an adjoining apartment house. Palmer then pulled onto the street, parked with his lights on, and used a two-way radio. He was not armed. He said he had just let off a friend. ”

“ If his conduct nevertheless satisfied the being-without-visible-or-lawful-business element of the ordinance, as the state courts must have held, it is quite unreasonable in our view to charge him with notice that such would be the construction of the ordinance. 'The underlying principle is that no man shall be held criminally responsible for conduct which he could not reasonably understand to be proscribed.' United States v. ”