It would be so much easier for me if I could wrap my presents before I leave for my Christmas night flight. It's a redeye so I basically go straight into Christmas #2. Is there any real reason they say not to do this? I don't understand how the machines can see through suitcases but not through a piece of paper.

The only catch is that I'd like to carry some on with me (too valuable to check), and check the unbreakable/bulky presents. Do they really unwrap everything or just if something is suspicious? I've got my dad a GPS unit that I'm not going to wrap because I figure that could look funny on an x-ray, but things like shirts and books seem ridiculous not to wrap ahead of time.