I understand that informing or not tends to be a personal preference...but I don't see how informing is cooperating more than not informing. Would you also inform of other items that are in the car? ...cell phone...McD's bag...etc?
That is the reason that many choose to notify...in hopes of "brotherhood recognition" leniency. But eventually you'll run into the LEO that doesn't want citizens carrying...will remove the gun for "officer safety"...extend the length of the stop to "run the numbers" something he has no reason to do...
I think the cooperating bit comes from what I said in the previous post. To most (cops) I think it says, "This guy has a weapon, but he wanted to let me know about it right away, he "cares" about me and my safety and knows that we face dangers" etc... You know what I mean? I guess I'm putting myself in their position. Knowing a citizen I was stopping has a weapon (legally) isn't going to change anything, but by that citizen informing me, it would show me that he cared and/or respected me enough to do so.
I don't think it has anything to do with a "brotherhood recognition", or at least not in my own personal choice, but regardless of the persons demeanor it can't hurt to do whatever you can to get on or stay on their good side. At least in my opinion.
As for cell phones or McD's bags, no, but they can't be used to kill him either.
When I have been stopped on my bike, when asked if I have any weapons (always seems to get asked anyway) I'd always mention the pocket knife I carried. Sure they didn't care, but again I think it just shows a willingness to cooperate that can't hurt, and just might help.