Bandit territory
An area or an industry, profession, etc, where rules and laws are ignored or flouted is bandit territory.
Barrack-room lawyer
(UK) A barrack-room lawyer is a person who gives opinions on things they are not qualified to speak about.
Kangaroo court
When people take the law into their own hands and form courts that are not legal, these are known as kangaroo court.
Law unto yourself
If somebody's a law unto themselves, they do what they believe is right regardless of what is generally accepted as correct.
Lay down the law If someone lays down the law, they tell people what to do and are authoritarian.
Letter of the law
If people interpret laws and regulations strictly, ignoring the ideas behind them, they follow the letter of the law.
Sod's law I always thought it was Murphy's Law
Sod's law states that if something can go wrong then it will.
Spirit of the law The spirit of the law is the idea or ideas that the people who made the law wanted to have effect.
