Yeah I guess their new drummer (who is Australian) had trouble getting into the US. They have a sub for the rest of the tour, but a friend of mine filled in for the Chicago show. I was worried I wouldn't get the full effect, but he did an amazing job and I was really blown away.
Also, FWIW, I'm in the process of starting a similar band here in Chicago. If anybody happens to read this and is interested, hit me up!