Comment by thaumasiotes

> such a rogue programmer would - in my books - be committing treason.

> Keep in mind that functioning rail system is of military importance

This sounds reasonable to me, and it made me curious how the US law of treason might apply to this scenario. (Obviously the US law is not relevant in Poland, but the American definition of treason is viewed as exceptionally strict, so it's interesting to consider.)

(American) treason has two elements:

     I. You owe allegiance to the United States; and

    II. You either:
        (a) levy war against the United States; or
        (b) give "aid and comfort" to the enemies of the United States.

A violation of criterion I might look like the Polish rail company hiring a Hungarian programmer who puts this code into the trains for whatever reason.

Making the trains stop running at predictable times seems like it could reasonably be read as "giving aid" to enemies of the state, if the information on how the trains work is communicated to them, or if a conflict actually occurs and the trains stop running during the conflict. If the enemy doesn't know about the issue and it never comes up during a conflict, it might be a challenge to argue that the enemy received "aid and comfort".

The other thing to note here is that the programmer would appear to be committing treason whether his boss told him to add the code or not.