As much as I oppose government intervention, I believe that spanking, and corporate punishment, should not be allowed past the age of 13 for hormonal/development purposes.
It wouldn't matter anyway, because by then, the child, if fostered correctly, would have already surpassed the stage where he/she has to decide what is right, and what is wrong.
13+ Punishments should revolve around the removal of recreational goods at the hands of the child.
Funny thing is, I'm grounded right now. the irony