Revive! Dead thread
This is the most recent thread I found with a forum search regarding lipo battery fires during the delivery process. Apparently this is not an issue in 2013. I ship from home or print my own shipping labels and drop off the package. I've shipped lipos dozens of times. Many people do. ONE TIME I was specifically asked by USPS employee if the packaged contained a high discharge lithium battery, but that particular time it only had a nimh.
Hobbyking recently amended their shipping policy of lipos. Chime in if you want, or this old thread goes back into the abyss...