But that all might change thanks to a new technology.
Across the pond, European authorities are conducting airport testings of a device called Insight100. The machine, developed by the company Cobalt Light Systems, is about the size of a microwave oven and can identify the contents of a bottle in a matter of seconds using a technique called Raman spectroscopy.
"A laser sends pulses into the container; a camera then captures those photons that managed to slip past the plastic, interact with the molecules in the liquid, and drift back out. Cobalt scientists have tailored their device to recognize the telltale patterns of scattered light associated with all the substances on the European Union’s threat list. When one of these materials, such as hydrogen peroxide or nitric acid, turns up, the Insight100’s screen flashes red. Water, shampoo, and that duty-free bottle of gin generate a green light."
And laboratory work shows a mere 0.5 percent of false positives.
But don't pack your 16 ounce liquid materials just yet. There will be ongoing tests for quite some time in European airports before it reaches the U.S.
Photo via flickr/Ben Popcken