I didn't try bringing a boxful on board today, but it may be possible to smuggle explosive or poison-gas precursors onboard using bouillon cubes, without requiring the participation of a dozen others as in the full bladder scheme.
The only major terrorist bombing of an airliner was carried out using a full pound of plastic explosive, set off by a barometric fuse, hidden in a fully functional tape deck. Accordingly, the TSA makes us take off our belts and shoes, regards breast milk with high suspicion, and forbids carrying on full bottles of contact-lens cleaner. If we were thinking of bringing explosive or poison precursors onboard as shampoo and conditioner, perhaps to be mixed on the suicide attackers head, it's not going to work. Gel colloids that can be squished out of a tube are out, but firmer gels that look like they're made from salt, hydrogenated oil, and autolyzed yeast extract may just make they cut; they seem solid to most people.
Barring that, bring on something that appears solid, with the chemicals micro-encapsulated inside (like scratch-and-sniff stickers). A plastic cube, a cell-phone case, a foam pillow, all could be insidious when combined with the complementary glass of water or when thrown in the toilet.
In order to keep us safe, TSA is going to have to rule out carry-ons altogether. Banning one phase of matter isn't enough; two others, and an infinite array of colloids, remain.
Those familiar with Frank Herbert's Dune may be worrying even more; not only can liquids be concealed in solids, but gases can perhaps be hidden in tissue. Prepare to get your teeth pulled if you want to fly!
Brickbat: Constitutional Scholar
3 hours ago