The padded envelops get ripped open by the sorting machines.

I had that happen last year. I sent photos to the seller and he was horrified! It is possible that he told others etc.

Our carrier suggested wrapping padded envelops along the back with slippery packing tape to avoid this type of damage, which happens commonly, according to her.

Here is a photo of this type of damage. The title of the photo reflects a vintage usage of a N word term, whose modern renaming was Nero. These European vintage leads are used for drawing with a special holder, and the two heavy small packs were at the bottom of this package and miraculously did not fall out. But it was delivered this way to me ripped straight across the back of the envelope! This is the photo I sent to the seller. He was very nice and when I several weeks later won another of a similar item from him he put in a 3rd package as a favor for my help ..he was a rare guy who appreciated knowing what happens in the mail.