I'll always notify, for my own protection... for the same reason that I always keep my hands in plain sight during a traffic stop:
The police are afraid of dying.
When they make a traffic stop, or encounter a potential suspect on foot, the possibility of being killed by the person they've stopped is always on their mind.
Long before I started carrying, a cop I knew explained this to me, and taught me proper ettiquette for a traffic stop:
0) Keep your registration and insurance card where you can get them without taking your hand out of sight even for a moment.
1) Pull over in a safe spot as soon as you realize the officer is going to stop you, instead of waiting for him to light up.
2) Open your windows, shut your engine off, and turn on the dome light if it's dark.
3) Put both hands on the top left quadrant of the steering wheel, and leave them there while the officer approaches your vehicle.
4) When the officer asks for your documents, hand him the registration and insurance, then tell him where your license is and slowly retrieve it.
5) Enjoy the ticket you don't get, or the lower-than-actual speed on the ticket you do get, and go on your way.
I have only been stopped once while carrying, on the PA Turnpike. I followed my rules, and handed the officer my LTCF with my license.
He asked where my gun was, I told him. He promptly gave me back my permit, wrote me a ticket for a much lower speed than I had been driving, and thanked me for keeping my hands in plain sight during the stop.