While I'm sure different attitudes will exist in different regions. Down my way, it's never been an issue, really. I've found, from OC in Ga., Az. and a couple other places that most folks either dont notice, dont care, will ask if you're a cop, or generally react positively.
It's a shame we have been conditioned in such a way to be nervous, or to expect adversity for carrying. But, I think that conditioning is largely self-inflicted.
I think also, it has a lot to do with how we carry ourselves,when OC, and how we present ourselves. If we went around trying to jump on the "fashion" band-wagon of hip-hop wannabes,and conducted ourselves accordingly, I doubt most reactions would be as positive or neutral. On those occasions I get to OC, I do so and just drive on like normal. I dont make a scene of it, or go around like "HEY LOOKY MEEEEE I GOTS A GUN" like some idiots have demonstrated a need to do.
Nor do I see a need to go out of my way to seek out cops to provoke into reaction on it, or to make some big political statement out of it. Just carry, drive on, be polite, and smile a lot. Most folks will nod in kind, and drive on themselves.