My accordions all got through fine. The clincher had been my main accordion getting shipped from Switzerland to Germany. I wasn't at home when the postman rang, so I got a notifucation card for fetching it at the post office next day earliest. It wasn't there. Over the next weeks a lot of phone calls, Emails, letters were sent. Apparently a truckload full of packages was misdirected right back into Switzerland. There was no way of stopping its progress while it made it to the border, passed custom in reverse and went on back to the sender where it arrived maybe 10 days later. The sender (probably on my suggestion) told his delivery person that both he and I still wanted the parcel delivered. Big mistake.
The Swiss post service had delivered the package to the German one and received its return. As far as they were concerned, they had done their job. The package ended in the "unwanted packages" queue in Chiasso, waiting for its destruction. A bunch of calls and Emails later, the package was back on the way to its sender again (the only option available) who, after paying a hefty fine on top of the posting fee and custom fees (minus the actual tolls which were added back when the package crossed back over the border), was able to receive it about 3 weeks after sending it.
Better luck next try, fortunately. I think the sender was sick enough of the instrument and process that he didn't even try reclaiming the lost money (all-in-all probably about CHF 70 plus all the effort). It probably would have been a fingerpointing and responsibility shifting and "we have no process for this" feast of the several involved post services anyway, so probably that choice was smarter than it seemed at the time to me.