Not necessarily a California question, but I wanted to know if this requirement was common in other states and if you comply.
North Carolina automatically recognizes concealed carry permits issued in any other state. To possess a concealed handgun in North Carolina (regardless of your home state), in addition to the usual prohibitions and requirements you must:
1. Disclose the fact that you have a valid concealed handgun permit when you are approached or addressed by any law enforcement officer in North Carolina.
2. If carrying, inform the officer that you are in possession of a concealed handgun.
I generally agree with keeping communication with LEOs to a minimum, but other states probably know if I have a permit and I would not want my silence to lead to a violation.