When I went last week, I was asked for my name and required to show ID. I assumed that for a larger party, they would just check the one person's ID, but there is alcohol served, so perhaps they check everyone's, and they require one match the name of the ticket buyer?
As far as the password, yes, they do ask for it as you enter the building, but by that point, you've already been ID'ed and checked off a list, so it's just for show. Silly, yes, but not uncharming.
That said, I will confess that I didn't enjoy the show very much. I've only ever seen Phantom once, roughly a million years ago, and I found some of the plotting tough to follow (who's this Raoul guy, and am I meant to care?). To my eyes, it felt like a fan-service event more than a show that's successful on its own. But I've certainly heard from people who found it thrilling, even if I didn't.