I recall when those guys in the UK (?) had their plan to explode a plane by mixing some volatile chemicals in the plane toilet. IIRC this kicked off the whole no liquids requirements. At the time I remember reading an article by a chemist on the chances of actually pulling off what they wee planning to do, and it was comical. To not just make a giant poof that mainly singed off some hair they needed to carefully mix the liquids in an ice bath for about 1h (without anyone noticing) and every little shake could potentially mess up the whole thing.

He then went on to what he considered dangerous and mentioned a couple of powders which you can easily bring on board which are much more devastating.