If I read my registration correctly, we can used our Enhanced Drivers License as documentation on a closed loop cruise? (Instead of Birth Certificate and Drivers License) For those who do not have a passport. Can anyone confirm that? Also, while on the topic - can anyone clarify what I would need for my 17 year old son. It appears it is a birth certificate and government issued ID. He does not have his drivers license yet. Registration mentions birth certificate and school ID - will that be sufficient? THANK YOU IN ADVANVCE!