system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] If there are things like potions that make people unable to lie and have to tell the truth, why are there things like courts and trials or even people like Sirius Black wrongfully jailed?

I feel like with things like that and time turners, you invent plot holes that wouldn’t otherwise exist. When Sirius was in Azkaban and had claimed prior that he was innocent and Wormtail was still alive, why wouldn’t he say “let me take some Veritaserum. If I am unable to tell you the same story, take me to Azkaban.”
gpt
There are ways around veritaserum, for example removing your memories and storing them in a pensieve for after you testify.  Dark wizards also got in the habit of using imperius on each other to commit crimes, that way both the person who actually did the murder and the person who did the imperius can truthfully say "I did not murder him".