I would not be surprised if this started out totally unrelated to explosives. Say that some toddler spilled an entire 3 liters of grape soda all over the plane. Or a hypochondriac brought cleaning agents aboard and gave everyone a headache.

Mostly sarcasm, but man do I see this pattern a lot. The risk mitigation apparatus is called in for something, they see an opportunity to overgeneralize and prevent an entire new category of potential mishaps, and the everyday folk end up really confused trying to reconcile the rules with their intent.

Reminds me of the parable about the bench guards. Is there an aphorism for this?