T-ara N4's performance at the Las Vegas Palms Pool wasn't met with the warmest response, and their label Core Contents Media explained that there appears to be some mix up in what type of event the girls were going to perform for.
CCM said, "We're flustered at the label, as well. We think there was some mix up and it happened because the concept of the concert was different. It was something promised from the beginning while we were talking details on recording 'Countryside Diary' with Chris Brown. Even the label won't know what really happened until after the American promotion team arrives on the evening of the 29th."
They added, "We were told that they'd be opening for a concert, but it was actually more like a festival-type event. It's true that Chris Brown and Wiz Khalifa planned the concert. The video is of their first performance. In their second performance, we heard that Chris Brown came out to introduce T-ara to the crowd."