There are people on the engagdet comment page saying they are in that improv group and they had the last meet last week. They didn't recieve emails for a meet this week so it is doubtful that it is them.
I read the opposite. I read people received emails for this particular event.
I don't think it's Improv Everywhere. I'm on the agent list and the last event they did was last friday.
Maybe some other group?
Not Improv Everywhere. I live in NY and take part in their brilliance. If something was going down i would have got the email but seems right up their alley.