The first time I saw the show there were four actors out (Charlotte, Natalie, Chrissie, and Heather) and when the cast came back on for the rehearsal number of "One," Alisan had left and her U/S took her place because she threw her back out. Natalie's U/S was amazing IMO. Charlotte's U/S...another story.
But the second time I saw the show the ENTIRE original revival cast was in and I must say...I enjoyed it more that time. The dynamic was better.
Sometimes I'm excited when I see an understudy. When I saw Piazza for the second time I saw Patti instead of Victoria and she was sensational!
But y'all are right...it's completely different for a tourist who doesn't know a lot about theatre. To them it is as if the show won't be as good.
"Somethin's comin', I don't know what it is but it is gonna be great!"