He knows the rules, if he does not register like he is supposed to, then they will keep locking him up. Why is he avoiding registration?

The Sex Offender Registration and Notification Act, also known as SORNA, is part of a comprehensive federal law that requires states to maintain a system for monitoring and tracking convicted sex offenders following their release into the community. The Act makes it a federal crime to knowingly fail to register with a state's authorities, or to fail to update registration at specified times, in accordance with the law's requirements.

Under the Sex Offender Registration and Notification Act, state convicted sex offenders who knowingly fail to register or update their registration can be prosecuted. Offenders may be required to pay fines and can face up to 10 years in prison. If an offender fails to register, and also commits a violent federal crime, he may face up to 30 years in prison.