Inspiration of this question comes from this answer: https://scifi.stackexchange.com/a/84596/
From the linked question:
For example, they have a system that will imprison a thief inside an impregnable vault and seal him up in there without sustenance for up to ten years. Does that sound like the kind of thing the ministry would approve of? (Well, considering Azkaban and the dementors, maybe.) And they were keeping a live dragon in London (well, under London) against all the rules. I don't think the Ministry can muster sufficient authority to discipline Gringotts and being the kind of bureaucrats they were, they were probably happy to see Gringotts embarrassed.
This is kind of funny, but 100% factual. Does Gringotts simply ignore laws by locking someone in a vault for 10 years? Or, does Gringotts get a special treatment from Ministry of Magic? Or, is Gringotts simply independent of wizarding laws maintaining own sovereign statue?