Well, for starters, we are a small town that uses PO Boxes and not mail delivery so the local postmaster knows most people who come in on a regular basis, and she sees what I get and send out regularly, so trying to say "Label Badges" won't work, LOL; plus all they have to do is pick it up and realize there is a solid mass in the envelope, with or without bubble wrap around it. Flexible, in this case, means anywhere in the envelope, so it can not bend at the pin itself, so it is a small package, not a large envelope.
Plus, in all fairness, if someone tries to "save a few bucks" by shipping it under the wrong classification, and then it can't be found, or becomes lost or damaged, then that really is not USPS's fault, is it? Trying to bypass the rules, IMO, serves not only to hurt USPS who is already hurting, but could mess up the trade.