Personally, and I think this is always a personal matter, I wouldn't have informed the officer that I was exercising a constitutional right. I know guns can be dangerous in certain situations, but you and I know the firearm was safer for everybody where it was in the car, untouched. If every time I heard of an individual telling an officer he was armed turned out to be uneventful and beneficial for the carrier, I might consider informing. But there is definitely an element of uncertainty with police officers (as with all people). You don't know if the officer will be a strong proponent of firearms or if he will freak out or if he will call for backup and keep you sitting around for ten minutes longer than he should have. For me I think the negatives outweigh the positives, so I won't be informing any officers if and when I get pulled over while armed.