The idea that "he earned his stripes" doesn't make much sense, EVERYBODY at any major has PIC time which means they were a CAPT somewhere, (even on the corp side). Of course a guy could wear his military dress blues or whites to work to show what he earned. I have a pretty cool "I love me wall" of things I've earned but thoes only make good conversation of what I DID not what I'm currently doing.
Someone had posted earlier that it takes away from the capt's authority in the plane if there are two guys wearing 4 stripes. What would get really confusing is if a capt had a line check and the LCA sat in the right seat, with an over 60 FE with 4 stripes sitting in the back.....