This should be illegal.
One method that does work in Australia is minimum course attendance hours. You get kicked out of the country if you don't meet these hours (because then you're not really studying).
The writing also is very much USA centric. This is the standard (almost?) anywhere in the world.
Japan? Work visa w/ sponsership or you spend $$ to a language school, culture, school, etc. Many Japanologists that have blogs about Japan do this e.g. enroll in a langauge school vs teaching english or getting a job job.
Australia and NZ is the opposite of the above and follows the USA example too. Just more expensive then Japan/Korea but the gold standard "seems" to be US/UK
The USA isn't the only one doing it.