The signed memorandum of understanding leaked by Time's Mark Halperin stated the moderator "will not ask any follow-up questions." So when Crowley went around before the debate saying things like, "Once the table is kind of set by the town-hall questioner, there is then time for me to say, 'Hey, wait a second, what about X, Y, Z?'" the campaigns got spooked. Halperin reported both campaigns "expressed concern" to the Commission on Presidential Debates over comments Crowley made threatening to ask follow up questions.
The Washington Post's Paul Farhi reports Frank Fahrenkopf, the debate co-chairman, isn't listening to the campaigns' complaints, and isn't worried about the memorandum. Crowley will be free to ask follow-up questions during tonight's town hall style debate. "Our position hasn’t changed," Fahrenkopf told the Post. "It’s exactly as we understood it when we announced the format and the moderator in July." The follow-up format was always supposed to be apart of tonight's debate. It wasn't a question until both campaigns complained.