The 100 mL liquid rule comes from a 2006 plot that police stopped with months of surveillance, not at a checkpoint. The shoe rule comes from one man in 2001. Both survived two decades after the threat faded.
The fix is not policy reform, it is hardware. 3D CT scanners can read the chemical makeup of a liquid through a sealed bottle. Heathrow spent $1.35 billion and now allows 2 L. Dublin dropped the 100 mL cap entirely. The rule did not change because someone decided it was wrong, it changed because a machine made it obsolete.
Source: Katherine Brodsky, Skeptic
