For those of you that are going crazy over this chumra, there is a reason for it. Matzos used to be around two or three inches thick, and mixed purely by hand- no tools. It would be very hard to have it perfectly mixed with every bit of flour getting wet. Often, there were bits of flour mixed into the matza. If that flour were to get wet, that would be chametz. True, now we no longer have this problem, but on pesach it is important to do whatever your parents did.
