Just a heads up here. I ordered a GA100MC from Zappos a few days ago, with free overnight shipping. I was surprised when it didn't show up and I didn't get a tracking number. I contacted customer service and was told that the watch was considered hazardous material and could not be shipped by air, due to the lithium battery (CR1220). I realize that there are regulations regarding shipping lithium batteries, but this is ridiculous. When I pointed out that Amazon was shipping the same watch in a different color overnight, it fell on deaf ears. They just kept repeating it was company policy.
I hope I don't have to leave my G-Shocks at home when I travel. Although if they become a banned item on airplanes, being a TSA agent could be a good gig for a G-Shock collector!