Your goal: invent a terrorist plot to hijack or blow up an airplane with a commonly carried item as a key component. The component should be so critical to the plot that the TSA will have no choice but to ban the item once the plot is uncovered. I want to see a plot horrific and ridiculous, but just plausible enough to take seriously… Terrorism is a real threat, but we’re not any safer through security measures that require us to correctly guess what the terrorists are going to do next.

Bruce Schneier