I send body jewelry and cards all with a do not bend all have arrived mint or all together. :) Has yet to happen to me. Not sure of they didn't put the do not bend but if they don't they send it thru the rollers and it breaks them out.
I just put the in a envelope with a stamp an put PLEASE DO NOT BEND on both sides all my gauges have made it safety out and I have feedback for it so its safe. :)