I played Quiz Bowl at Berkeley with Matt Bruce, and I can fill in some details. I wasn't there when Matt made the "pecan pie"/"crack cocaine" buzz, but an important bit of context is that there was a previous "trash" tournament (perhaps the Ann B. Davis tournament?) that featured a toss-up question that was primarily derived from a list of instructions about how to make crack cocaine. In fact, I remember playing on the crack cocaine question against somebody in Quiz Bowl practice (I believe it was Ryan Gant) who got the answer very quickly after hearing some basic clues about the oven temperature and some minor ingredients. In a later tournament, when Matt Bruce heard a question mention an oven temperature, he must have thought the questions were similar and reflexively buzzed in with "crack cocaine."
By the way, I think my worst all-time buzz is when I answered "Yo-Yo Ma" when the correct answer was "Jet Li."