I disagree - I feel that there is no need for LEO's to be able to identify what you say are those who "legally" OC. I feel that there is a need for education of LEO's so that they don't violate anyone's civil rights. You don't have to post your driver's license on your car window, and driving is a privilege, not a right. OC is a constitutionally protected right (2nd Amendment) and therefore should not even require any kind of permit or license. Displaying some kind of credential to OC would be equivalent to having to get a permit and have it on display at all times when you are speaking to anyone (1st Amendment).