I can’t define it, but it’s here to stay

Several plaintiffs brought a class action against Clear Channel Communications for, in essence, monopolizing the market for putting on rock concerts. They sought to have the case certified as a class action on behalf of all purchasers of rock concert tickets — the group allegedly victimized by the lack of competition.
One of the requirements for class certification is a showing that the class is so numerous that joinder of all class members is impracticable. Plaintiffs alleged that there are thousands of purchasers of rock concert tickets in the geographic area covered by the lawsuit and that these individuals are geographically dispersed.
Clear Channel responded that the class is not ascertainable because “rock” cannot be defined.
BY THE WAY: The court ruled that “rock” need not be defined for purposes of determining whether the class is sufficiently numerous, because under any definition thousands of individuals will have purchased tickets for rock concerts.
Like I said, it’s here to stay.