I once took an exit off a local freeway after the white line went solid and I was about to miss it. I still have no idea where the Highway Patrolman was, but he pulled me over for it. When this rookie came to my window, I informed him I was packing (I don't always, and can't tell you why I choose to at that time.) Anyway, his reaction is why I usually do not inform anymore. "For Officer Safety" he asked me to step out so he could disarm me. I'm not nearly as smart about this stuff as I am now, let me tell you.
So anyway, this 20-year old kid packing a double-action Sig Sauer, that has probably been the only gun he's ever known, has me put my hands on my head while he tries to extract my cocked-and-locked 1911 from an IWB, while I pray that he doesn't shoot me with it on accident. Finally I asked him if he would just draw the entire holster with the sidearm inside it. He agreed (it's a good thing I'm one of the good guys).
Moral of the story is: If I was a bad guy, I wouldn't have bothered with the 1911 in my IWB. I'd have shot him with the Walther in the unlocked console that he never even knew about.
On topic because: what! you guys don't have a second sidearm for the car?
*I used to make it a habit to inform the officer that I was carrying because I found that I got a lot more warnings instead of speeding tickets that way, believe it or not. I don't get pulled over a LOT, mind you, I'm basing these experiences over the course of two decades. It seems that if the cop has a LEGAL firearm to "deal with", he has spent some time on the issue, and by the time he is satisfied with it, he's had me pulled over long enough that I often got a warning for the actual "crime" I was committing.