Have always brought everything extra, ML, BC, Student ID's. Last Cruise went on with my Wife she forgot everything. This was few yrs post 9/11 and today wouldn't work but I had Original copies of our ML, our BC's plus my DL & Mil ID. Airline gave us hard time but still got on, Cruise Line was easier.... My Kids are 25, 28 and 32 and I still have Original copies of their BC's