This has been very frustrating for me as well. I sell on ebay and recently had 5 FRE returned to me! They said they were too full and I used too much tape.
Fortunately they didn't ruin the labels and I was able to use the padded FRE so my buyer got all her packages.
Now I use those Tyvek envelopes and put the contents in them and then in the padded FRE just as extra safety.
So far so good.