Double boxing is the minimum you should insist on. I asked my shipper to do this when he shipped a pair of speakers to me overseas.
The box arrived with one corner badly compacted. It was obviously dropped. I did a prayer. I opened the 2 boxes and discovered one speaker was improperly packed with a large foam buffer missing. The speaker had fallen on the impact to within a whisker of the bottom of the box. The double box saved it from being damaged.
The box arrived with one corner badly compacted. It was obviously dropped. I did a prayer. I opened the 2 boxes and discovered one speaker was improperly packed with a large foam buffer missing. The speaker had fallen on the impact to within a whisker of the bottom of the box. The double box saved it from being damaged.