Some states require you to notify LE if you are pulled over and are legally carrying a handgun. The problem with this is that some officers don't give the person a chance to speak, and when they finally do, it's too late for the LE. This is an example of a case like that.
http://ohioccw.org/201107214955/cantonpd.html
http://ohioccw.org/201107214955/cantonpd.html