I suggest you play cyberpunk 2077 to see what happends in a city with almost no rules. The idea seems good in theory, but falls flat in practice. such places would have enormous allure, when announced hundreds of thousands would trek there, in the hopes of striking it rich through less than ethical means, companies and facilities would thrive since minimum salary is just a suggestion. These cities would become economic powerhouses of depravity. With power comes influence and slowly they will try to infiltrate the government that is supposed to uphold the law in the rest of the country. This is even further accelerated because people go where the money flows. Populations grow, the city grows, economy grows and degredations continue. This cycle repeats until there is no difference between country and city.