Nobody whose review was published tonight saw the show tonight, and not just because there was no performance tonight. The idea that the show went on yet a different audience was kept waiting and then sent away is awfully out there.
It seems reasonable to think that everybody inside the theatre really really wanted to have a performance tonight, and the delayed opening of the house and last-minute cancellation were because they were hoping they could possibly go on. Whether they were trying to talk RSH out of going on or into it, or just having a quick walk through the show to see if it could happen, who knows. It's not as if they could send on an understudy, if there's even one prepared.