“In most cases it is only a recommendation that you notify the officer, but it is not required.”
In Ohio it’s a requirement if the contact with the officer is an “official contact”. That means that if you and an officer are casually discussing Sunday’s game in line at McD’s, there’s no need to notify. If the officer starts to interview you about the robbery at McD’s, you need to notify.
I thought this was true in most cases. In Wisconsin, it is not required, only recommended. Most responsible CCW permit holders will notify the officer upon a stop. I certainly would. It makes for a much more polite interaction with an officer. I guess not in this case.