I can't speak for all bike packers, having learned a couple of hard lessons myself.
However, for the purposes of this thread, in C&V.
1-Kurt is right spanking on.
2-If you're shipping to a bike person, find out if they can assemble. If so, disassemble.
3-If you are getting paid to get a pristine bike to an owner, pack it so, and pay for it.
4-If you are not, do the best you can, as if you were shipping it to yourself.
5-Do not depend on any shipper to accept blame, even if they destroy the box. They won't.

Receiving bikes, try to take the time to open the bike in the presence of the delivery guy. They really don't like that, but turning it over to the OS&D person prevents the claim process. They may take it back from you, and gladly pay a small repair fee in lieu of sending the whole bike back.

If it gets to the claims department, then you're pretty much screwed, because they'll blame others.

I only know that on collectible bikes, I've only really sent two, and I packed them with 100% prevention in mind, barring collisions. It was expensive, it took a long time and a lot of packing and tape, but both recipients were 100% pleased. I know they had a mess on their hands, but the bikes were OK, and one was to Australia.

It's just a part of this business, I guess.