The layers we use to keep shipped cookies from shifting, with an honest note on what customers have reported.
We seal our cookies in kraft sleeves, place them in a kraft box, then cushion that box inside the shipping carton so it cannot shift in transit. We have shipped all of our cookie varieties this way, and no customer has reported breakage to us.
We freeze finished cookies before shipping because we find they stay fresh and moist. We have not run a controlled transit study, so our experience is a method to try, not a promise that every parcel will arrive perfectly.