Just wanted to provide a quick update. No paper form to fill out, signed up despite it being only my second visit to Hong Kong ever. Used my UA 1K status card. I intentionally attempted to use my AA EXP card first, having not seen anyone post here or elsewhere that they had tried (not to say that nobody has tried) due to AA starting to fly to HKG this year, but my agent looked at the book and said the AA card was not currently accepted.