In some countries it's done so and poisoning is banned. E.g. Finland and Poland got an exemption from the EU to do this because so many people died from the poisonings.
https://en.wikipedia.org/wiki/Denatonium is used to make it unpalatable. Fun fact: the same chemical is also coated onto Nintendo Switch cartridges to discourage children from putting them in their mouths.
Nowadays we just measure pressure differentials.
Methanol sales were banned in Finland prior to EU and Finland applied for the exemption already in the EU application in the early 1990s. It was finally granted in 2019. Probably around 500 people died and many got blinded meanwhile.