The ready availability of Zone of Truthwould certainly have an impact on the legal system.
Picture this situation. The police have coerced a false confession out of a suspect. He is put on the stand. The witness chair is enchanted with a permantent Zone of Truth.The witness can't lie. The confession is shown to be false, and the interrogating officers are in loads of trouble.
At the same time, Zone of Truthwould eliminate any need to ban a suspect testifying against himself, since no-one would be able to falsely testify against themselves.
Picture this situation. The police have coerced a false confession out of a suspect. He is put on the stand. The witness chair is enchanted with a permantent Zone of Truth.The witness can't lie. The confession is shown to be false, and the interrogating officers are in loads of trouble.
At the same time, Zone of Truthwould eliminate any need to ban a suspect testifying against himself, since no-one would be able to falsely testify against themselves.