Always felt that part of the penance where a crime has been committed is to "turn yourself in".
The seal of confession: In our little Catholic neighborhood, it meant he wouldn't tell mom.
As Caridi said, the priest can make absolution contingent upon the offender turning himself in to the authorities. And no, no “anonymous tips.” That is exactly what is known as “breaking the seal.”
Part of the Christian ethic for getting forgiveness from God has always involved taking responsibility and making amends for the wrong done.