I have seen threads on this in the past but thought this was worth sharing especially the story at the bottom of the article about the 50's Martin D-18 he received in his shop. Sorry if it's been posted in the past and I missed it.
http://www.bryankimsey.com/shipping/
Bryan is well respected over at the Martin Forum and always offers interesting insights.
On the subject of guitar cases, they all have benefits and limitations just like a helmet (Football, Motorcycle or Darth Vader's) and are designed to protect but not guaranteed to prevent damage.
Hi teh,
Here is a link to the Larrivée instructions for shipping your guitar (http://www.larrivee.com/5_features/educationEssays/shipping.html).
Interesting differences and discussions especially related to string tension and use of foam chips.
I'm not suggesting that one source is more credible than the other, but I know what I would do if I was shipping to Larrivée.
I ship mine in the same box I get them in. And everytime it gives me a little panic attack,lol. My understanding is that it's very important that the headstock is supported. In fact, I leave that paper in the cases for a little protection when they leave the house.
holly