With no detectable fanfare, the Los Angeles Times has spiked a special advertising section tied to a costly downtown Labor Day–weekend extravaganza called “The Celebration at City Hall.”Times corporate declined to explain the about-face, but there’s no doubt that the organization wants to avoid any comparisons with the 1999 Staples Center embarrassment, when the Times got hammered for mingling editorial and advertising prerogatives in a special edition of the Sunday magazine that “celebrated” the arena’s opening.“We are not planning to distribute the special advertising section,” said Times corporate spokeswoman Martha Goldstein. “There is no comment beyond that.”