Obligatory, judicial, slap on the wrist
a slap on the wrist so weak it could be mistaken for a handshake from a confused baby
He got a slap on the wrist for throwing a tantrum in the grocery store and then bought a whole cart of candy.
The judge gave her a slap on the wrist for skipping school and then said, 'Go get some sleep.'
He got a slap on the wrist for cheating on a test and then laughed it off.