Will everyone know the punishments for crimes in an Islamic state, and will someone who commits a crime without knowing its punishment be punished?

Islam has specified punishments for certain crimes, and left the estimation of some discretionary punishments (ta'zeerat) to the ruler. Whoever commits a crime deserves punishment unless excused by ignorance, but the excuse of ignorance varies according to issues and individuals. Ignorance of the prohibition of something common among most people is not accepted as an excuse unless one is a recent convert to Islam or grew up in a remote desert. However, ignorance of the punishment, while knowing the prohibition, is not an excuse.