(Apologies if this is the same question that gets asked in every thread of this kind; I freely admit to not having researched this.)

What motive would the conspirators have for demolishing WTC7 with explosives? If they wanted to start a war or increase wiretapping or get Bush re-elected, or whatever the motive was, flying planes into the towers was enough. Blowing up WTC7, and especially blowing up WTC7 without arranging a plausible explanation (like "a plane flew into it", as they did with the towers) seems careless and unnecessary - out of character for a group of people careful and competent enough to arrange 9/11 and get away with it.