I am not sure why they couldn't do a couple of runs. One for press, so they could do the obligatory walk through videos and interviews without geeky spotters in the background, and people measuring seat pitches and the thickness of cushions..
..and then one for other people who had been told on social media or the website about the event, who could come along and look around - maybe even do the same run again.
It would have been good for publicity and reputation, especially as they Tweeted about it all morning to brag about it.
But, hey, that's what I'd have done.
What's going to happen now is that they'll introduce the train into service and find that loads of extra people turn up. They'll probably run the train on a busy commuter service or something, causing chaos.