In "Family", Worf's adoptive father, Sergey Rozhenko beams aboard and is instantly buddies with Chief O'Brien (from his point of view).
WORF: They still have not signalled?
O'BRIEN: No sir.
FEMALE [OC]: Enterprise, this is Earth Station Bobruisk. Two to transport aboard.
(A big, stocky silver-haired man, and a mature woman with lots of brown hair appear)
WORF: Mother. Father.
SERGEY: You look good, son. Put on a little weight, huh?
SERGEY: Sure you have. Looks good on you. Still working out with those Holodeck monsters, I bet.
WORF: Let me take you to
SERGEY: Always good to meet another Chief Petty Officer. Sergey Rozhenko, formerly of the USS Intrepid.
O'BRIEN: Miles Edward O'Brien, sir. Good to meet you.
SERGEY: Don't call me sir. I used to work for a living.
How does he know O'Brien is not an officer and know his rank? None of the possibilities I can think of ring true for the script:
Sergey knew ahead of time who would be operating the transporter or at least heard his rank at the origin (doubtful -- there is no previous dialog and why would passengers know this ahead of time)
Sergey already knew of Chief O'Brien and knew enough to recognize him (doubtful)
Something on O'Brien's uniform or appearance (I don't think so)
Transporter is always operated by a CPO (Very doubtful and there's probably a counter example)
Script was edited and previously Chief O'Brien was introduced to him (awkward and out of place -- why?)