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.
We used to use denatonium (Bitrex) in firefighting to test the efficacy of your face mask seal - you'd put on your mask, a filter, and a hood - Bitrex would be aerosolized into the hood and if you could taste it, there was not a good seal.
It was specifically about methanol. Methanol wasn't explicitly used as a denaturation agent but ethanol methanol mixture sales were (forced to be) allowed. Can't find much in English but here's a brief story.
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.
