Packaging is interesting isn't it. I have not shipped out a lot but I have had my own funny stories. It seems to me that movement is the real key. If you are able to prevent the miniatures from jostling around you'll be okay. Some people think the trick is filling the package with styrofom all the way up to the top as if the miniatures will magically suspend themselves around the filler and not touch each other. My wife got these little mini ziplock bags that are perfect. I have one guy who sends me all his painted miniatures in jewlery boxes with felt inside. I'm always nervouse to open them up, but it always works!
The best shipper is Uncle Mike who shipped me two painted minis if a foam container box with each miniature in there own little slot.
Figures not moving is good, except if you do what I once did ...
I was sending out one of those large GW flying beasties with a rider on top, nicely painted so I wanted it to be well protected. My 'brilliant' idea was to blu-tak, and I mean REALLY blu-tak the base to the bottom of the box to ensure it didn't rattle around inside and ruin the paint job. The empty space was filled with foam peanuts and the package sent ...
Well, the base didn't didn't budge, however the forces imparted on the box during it's travels were so great that the beastie snapped off the ankles!

After that, on advise from the web, I developed my 'cocoon' method: Wrap the figure in a layer of bubble wrap, then wrap completely in toilet paper, again and again until you have a 'ball' of paper that is quite solid. Place these in a box filled with foam peanuts and you are good to go, haven't had a problem since.
Cheers!
Joe Thomlinson