Water at airport security

I suspect airline passengers are asked to dispose of water and other liquids at airport security because officials are concerned that they may try to smuggle toxic chemicals or alcohol onboard. But, to me, it'd be just as effective to challenge passengers to take a swig to prove that their liquids are benign. No one would be able to consume these dangerous liquids without coughing or facial contortions. And, if security officers remain unconvinced, they can ask for a sample so that they can smell it or run tests, like they do with formula and breast milk.

The status quo adds a pretty big inconvenience with minimal security benefits; people can still carry liquids that go unquestioned as long as they're in small containers. If someone were determined to get liquids through, it'd be pretty easy to exploit this vulnerability.