If you dont let an cop know that you are armed and he sees the weapon without you pointing it out, you could get shot.
I openly carry rifles and shotguns in my vehicle all the time. If a cop shoots me simply at the sight of a firearm he probably should be sent to prison for the rest of his life, or executed for murder.
I have yet to run into a Law Enforcement officer that goes into full panic simply at the sight of a gun.
As an ex LEO, during a routine stop, I would rather the driver tell me they have a gun in the car but if they don't and I haven't asked, it's not a big deal in most cases.
As far as shooting someone just because I see a gun, that is ridiculous.
My car handguns are in this position.
A couple years ago I was stopped for speeding. I was actually feeling bad and when the State Trooper came up to the window I said, "Do you mind if I step outside the car?"
"No problem".
I handed the Trooper my DL and CHL and said, "I don't have a gun on me but I do have guns in the car".
The Trooper said, "You mean the one by your seat?"
I said, "Yes, that's one of them", and that ended any more talk about guns.
I suppose in some states the sight of a gun freaks the LEO out. Thankfully that's not the case in Texas.
BTW I didn't get a ticket.