Agreed, not a big deal. It's not a status in as much as it is a title. It's not Mr. Smith or Dr. Smith, it's CPT Smith.

As a civilian, it’s perfectly acceptable to address the service member by rank only. I have been referred to in this manner, and there is nothing wrong with it at all.

A few tips as you interact with these service members in an informal nature, feel free to take and use them as you wish. You might already know them, so ignore where appropriate. I am a former army officer, so some of these are not applicable to all services:

If a service member has no visible rank while in ACUs, meaning they have a fuzzy patch in the middle of their chest, they are a private.

If you can recognize the Master Sergeant/First Sergeant/Sergeant Major ranks, address those individuals as such rather than simply “sergeant.”

Lieutenant is fine. For the Army/Air Force/Corps, don’t differentiate between Second and First Lieutenants.

For Lieutenant Colonels, drop the lieutenant. “Colonel” will do.

All flag officers are simply “general.”

For the navy, the officer rank symbols are the same, but the titles are completely different. An Army captain is the same rank as Navy lieutenant, for instance. You're on your own for naval enlisted ranks. Between the ratings and rankings...I get a popsicle headache. I've never figured it out.

Good luck. Let me know if I can help further.