The time to make a case for changing the law is before you get caught, not afterwards.
The time to argue against a law that has an unjust punishment is anytime. Certainly for someone like me who has never been caught, but those who get caught have every right to rail against opressive punishment. Of course, it's up to the public and legal system to agree if it is opressive or not, much like it's up for the supporters of the punishment to validate that support, and for the opponenets of it to invalidate it.