I was concerned about this issue too.
I flew UX last week, MAD to FCO. All I can say is that I only had one bag and it was under 20k and I did not get charged. I asked for my DL number to be input and I was given an exit row seat. It was quite decent service, overall.
Except that UX hasn't credited to SM yet. Whether it ever will or not, who can know. It would be too depressing for this failure to be yet another :-: best in class :-: performance by SM but I don't know how long crediting takes so I can't say that...yet.