Make sure to get your DD/DS back well before the expiration of liberty. They have to be in formation by the designated time, not just arriving on campus. It is a very bad idea to be late or even to be the last one to arrive back just before the set time. On his plebe Christmas liberty, our DS had a connecting flight get cancelled, his bag was lost by the airlines, and he arrived back at KP at 0330 the morning after liberty expired. Suffice it to say, the extra attention he received for the next couple weeks was not fun!