Recording any "exception" items on the back of the boarding passes is WRONG. Many airlines keep the boarding pass (or at least a large part of it), and so now the federal government will be forcing people to essentially disclose to the airlines (and anyone else who gets a hold of the trashed boarding passes) any medical conditions or personal items that they brought with them. Items that are allowed as exceptions are of no threat and hence should not have to be disclosed to the airlines.