I want to tutor and teach guitar after school in China, but it's technically illegal. Basically, the law says that you can't teach anybody anything without a work visa. And this work visa will not let you work anywhere except for your place of work. Therefore, private tutoring done outside of your place of work is technically illegal.
Yet, how do you define tutoring? A friend showing another friend some chords on the guitar is technically tutoring. A Chinese person teaching an American friend some new words is technically tutoring. A grandfather teaching his grandson how to play baseball is technically tutoring. A police officer explaining the illegality of tutoring is actually tutoring.
Of course, in all of these instances, there isn't an exchange of money. It's just friends helping friends. So, perhaps the illegality occurs when there's a monetary exchange. In America, there is a section on tax forms called "miscellaneous income," because the American government realizes that miscellaneous income is a part of normal life. For example, winning some money at a raffle, helping to paint a friend's house, private tutoring, getting paid to mow your neighbor's lawn or making some extra cash helping a friend move could all be miscellaneous income. Rather than simply requiring all of the above transactions to require a work Visa, China would be wise in creating an option for miscellaneous income. This will only increase revenue for the Chinese government and allow people to stop hiding their respectable side jobs.