This is bizarre. Not sure why after soo many years, this question and the answers have popped up in my email. I even forgot I asked it. Well, here's an update: My husband at the time went ahead and celebrated before pinning on the new rank. I did not join that party - that's how strongly I felt about jinxing it. The party was hosted by his coworker, who also was promoted. But when he did officially put on the rank a month or so later, I threw him a proper surprise party, and it was swell.... Fast forward about 4 yrs from that promotion, and another promotion came up. He waited for his 'line number,' and when it was time, an official promotion ceremony was planned and took place, with the chief and everybody. A couple weeks later, he comes to find that in fact, it wasn't yet his turn to pin on the rank; he had about another month to go. There was a misunderstanding about the date of the promotion. Since he had been wearing the extra stripe on his sleeve for a couple weeks, he was told to go home immediately and put on a proper uniform, one with one less stripe on. He did not leave immediately; he took his time. He got in a lot of hot water for that infraction. There was talk of Article 15. Almost got kicked out of the service because of it (impersonating NCO). As 'punishment' his promotion was postponed by about 5 months (with no retro pay once the new rank was pinned on), our PCS as a result was also delayed. It was a huge stressor, a real terrible situation.
So the point in all this is that it may have taken 4 or 5 years -- I believe karma took its time in coming around, but it ultimately did come back to bite him for partying before officially being promoted.