Whether you take it in the original box or in something else, the key thing is to pack it tightly. I can virtually guarantee that the box will be shifted around, flipped upside down, may be dropped, etc. You can write "This Side Up" on the box, but that will probably be ignored. I would recommend putting it in something else, simply because of the logo. If it is in the original box, some rampers may be curious and may actually look in it (even though that is a big no-no). I can't imagine how someone could sneak at ~25'' box out of the secure are, but I'm sure it is done.

EDIT: All that being said, the chance of someone stealing it out of the secure area is very slim. Small items are one thing, but a large box is another.