> You are arguing that the risk of accidental poisoning by methanol is in fact high.

I’m arguing that no level of introduced “deterrent” fatality risk is an acceptable trade off for preventing a crime that itself isn’t punishable by death (and I believe that no crime should be punishable by death).

The only situation I would consider deliberately introducing the risk of fatality as a deterrent, is when there’s extremely clear evidence that such a deterrent lowers the overall fatality risk associated with the crime, by reducing harm to victims, or to the perpetrators themselves.

> methanol poisoning is often used in situations where the potential drinkers are highly informed, e.g., people ordering chemicals out of a catalog.

It’s also used in plenty of situations where potential drinks are completely uninformed. Such as when bought for the purpose of paint thinning, camping stoves, and as a cleaning product. Plenty of situations where a completely uniformed individual may purchase the denatured alcohol, or have easy access to denatured alcohol.

> Importantly, your argument is not the one I was rebutting, that poisons are bad disincentives because they are inhumane punishments for tax evasion.

I can provide a pretty simple rebuttal to idea that poisons are good disincentive to prevent tax evasion. If you’re not educated on the process of methylating spirits to make alcohol undrinkable, then by the time you’ve drunk enough of it to figure it out, you’re dead.

Now in a an extremely pragmatic way, that makes poisons extremely effective at preventing tax evasion. Those educated enough to know better don’t try to evade the tax, those that do die. This all evaders are either discouraged or eliminated. Of course one issue with this is assuming the person consuming the substance is the same person that evaded the tax. There have been plenty of cases of people diluting normal alcohol with methylated spirits to bulk up their stock, in the process making the assumption the dilution is great enough to avoid poisoning people, or that they won’t be around to face the consequences.

I think as a society we’ve agreed that this sort of absolutist approach to law and order is pretty barbaric and unbecoming of a more civilised society.

> It's the equivalent of deciding the punishment for tax evasion is to execute one in every hundred tax evaders.

> It's not, both in terms of numbers and in terms of principle.

You’re right. It’s closer to killing a random small proportion of tax evaders, and also killing a random small proportion of anyone who’s had the misfortune of doing business with them.

> You have misinterpreted my comment. I did not refer to protective barriers. There are plenty of examples where metal posts and concrete barriers are used to stop cars from getting to places where they would be a nuisance but not dangerous (e.g., pay parking lots, dedicated express lanes, and "no thru traffic" barriers).

Again, it’s obvious to anybody what a physical barrier will do to their car, protective or otherwise. It’s pretty hard to conceal a physical barrier in a manner that would cause someone to unknowingly drive into it. Unlike methylated sprits where’s it trivial to conceal its nature.