I don't know man...the whole "bringing Jack and Coke" seems like if it was supplied as advice it would be the best.
Consider this situation. A neighbor/cop who works in a different parish, i.e. out of jurisdiction, parks his "unit" illegally. Why? LOL Come on - this is Louisiana and public safety takes a back seat when one's manhood is on the line.
Do you have to inform him that you are carrying when you ask him to kindly abide by traffic laws and move closer to the curb so his "unit" does not interfere with safety?
If he works for a different parish, then I don't see how it could be "official business".
Regardless, he's just a person. Forget about the lights and stickers on the car and go talk to him like one. He may have a good reason for parking like that, or may have no idea that it bothered anyone.
I wouldn't feel the need to disclose that you're carrying if you're approaching him as a neighbor, and not confronting him as an officer. Just go talk to the guy. Chances are, he's not the big bad wolf, and he may be parking where he is for good reason. His answer may surprise you.
We had a problem with people speeding on my street a couple years ago, and quite a few of us parked off the curb and closer to the street. It helped forced people to slow down when passing, and significantly reduced the average cars speed. Maybe that's all he is doing.
Have you told him to move yet?