just read from the HK Yahoo news (in Chinese) that there WAS a test run involving 60,000 people yesterday (17 Oct Sun). Though it was a trial run, the participants had to PAY for their rides which caused a lot of unhappiness.

Suggestions (a very nice word for complaints, haha) brought up were:
1) Inadequate signage
2) The passagewalk to take the line which crosses the sea (?) was too long

On the whole, the trial was successful and the new line will open officially on 24 Oct 2004 Sun @ 1500hrs. not sure when this URL will expire but if you are able to read traditional Chinese, here is the full article
http://hk.news.yahoo.com/041017/10/15sjy.html

* amended suggestion #2 which had the airport error