The first date of the When We Were Young Festival in Las Vegas was cancelled due to dangerously high winds. While many bands were able to secure other venues and have secret shows that night to not leave fans disappointed, some fans decided they would go see Katy Perry at her Las Vegas residency instead. She did perform on The Vans Warped Tour in 2008 after all...
I cannot believe she invited a fan on stage to "mosh". I love her!