The usher I spoke to said that on some occasions, when the boom was lowered and bad news had to be given to the cast, it was announced just before they went on stage to do a show. Pretty bad form to be told, for example, you've been sacked right as places is being called. Now that I think back about it, seems to me this is probably just what happened to the Civil War cast the night I saw it.
They were also given a number of comps so that they could invite friends/family/whomever to the show. As soon as the producers pulled their monies out, all comps were rescinded. As the usher told it, some of the cast had some really great industry connections that might have come and spread good word of mouth.
I really don't know what SOP is in these situations; are comps pulled when other shows close as well? I would be bummed and perhaps a little mortified if I had invited 3-4 friends to see a show I had managed to comp them for and then tell them they have to pay.
For the record, I was treated very kindly by the guy at the box office. I didn't want to wait at TKTS, so I went to the theater armed with my discount code. I asked for a rear mezz seat and the guy was kind enough to sell me one with the code before I even gave it to him. $59.50 for the evening which I thought was more than reasonable.
"Sticks and stones, sister. Here, have a Valium!"