Justin Timberlake is accused of not singing much during his recent world tour. Didier Messens/Getty ImagesEach year, millions of people purchase tickets to see their favorite artists live in concert - and that number is only growing. And while Taylor Swift may not currently be performing, following the end of her nearly two-year Eras Tour, other stars, such as Beyoncé and Coldplay, are filling in the gap, attracting massive crowds and making headlines.But several recent concerts have made waves this summer for reasons unrelated to the music.