Encores are expected and programmed anyway. I know the excitement of seeing the band come back on stage, feeling that you're getting more, but it's all written down already in the setlist. Knowing it before will make easier to accept that they won't come back.
To do what, anyway? I'm sure that after 2 hours and counting of the show, the ending with the title track will be completely fulfilling. No need to see Metropolis at the end, not that I wouldn't mind, but I'm sure it will make sense at the show.