Well, Capt old chap, believe it or not, by express direction of our employers, we are told that the full fare paying pax do NOT want to know anything about the F/O and SPECIFICALLY if he is flying the a/c!!
However, some may protest this by not making any PA's as Capt and letting the F/O do the lot on his [hs usage] sector, unless some greater operational requirement comes up. They are still NOT told that the F/O is actually FLYING the a/c, and so corporate direction is faithfully obeyed.
Some guys do announce who the F/O is and also add surname.
G'day
