I used to work at a local shipping store in Denver and learned a little bit about insurance via UPS and FedEx. Granted, the bulk of this conversation is regards to international but I'll throw in regardless. Every day when our driver would pick the days packages he would immediately ask two things, is there overnight and are there parcels worth more than $5000? Those were priority to him. They even had a special place on the truck for both things. Out of curiosity I asked him why $5000 and he said that when they got them back to the hub they were taken off by the driver personally rather than the night crew of randoms that unload the truck and that they skipped the conveyer belt systems all together. Otherwise, you could write fragile, glass, baby pups, whatever on the box and it doesn't really mean squat. The only other sticker they paid attention to at all was a +75lbs sticker so they didn't throw out their backs.
Overall, insurance is only going to be paid out if the item was packaged correctly. Over the last few years UPS had gotten real stickler about it. If you went into a UPS store with your own box they would always warn that if you insure it for more than the $100 it automatically comes with, it won't be paid out if it's not to UPS standards and that they should be the ones packing it so you get that guarantee. I've seen a lot of expensive items (well over $1000) get held by UPS for months waiting for their internal insurance adjuster guy to show up and take a look at it and deem it worthy or unworthy of a claim.
As a manager at the theaters we received tubes like the one in the picture above and worse and time and time again our driver would say sorry, they all ride the same conveyer and sometimes awkward items get stuck or knocked around. Only recourse was to refuse the package.
I don't know, so far the most impressive packaging I've seen is Bruce's although I've not bought from other auction folks on this site (plan to soon though!). As for international and customs, good luck cause it seems like there is NO rhyme or reason because it's different for each country. We had a phone book size book that detailed every country with restrictions and rules and blah blah blah. I do know that value should match the insurance to get it through faster. So at the end of the day, pack it right so it can be insured correctly and make sure the seller has a money back guarantee on his product AND his packaging. I've heard of people mailing their own tubes to sellers to use like fishing pole tubes and map cases and such for bullet proof protection. I guess if it's worth enough, it's worth a little more leg work to make sure it gets there.
My .02
