No, this kid is not the most dangerous person in China. In fact, he was quite innocent and rather excited to have a conversation, in Chinese, with a foreigner.
The most dangerous person in China is the foreigner with excellent language skills but is clueless when it comes to culture, especially behavioral culture. The problem is that if you have really good Chinese, the Chinese will expect that you know how to play the game; they will expect you to behave like they do. Cultural coherence refers to speaking and acting like Chinese expect people to speak and act. If someone has good speaking skills but acts like a typical American, they will undoubtedly offend people. In fact, the Chinese will most likely believe that you intended to offend them. Again, to the Chinese good Chinese means that you should know how to behave yourself. For example, the American with good Chinese uses typical American sarcasm with his Chinese colleagues and they are offended because they simply don’t understand American sarcasm. Sometimes we call this speaking English in Chinese.
It is simply impossible to separate language from culture. All communicative situations are situated within a cultural context. For language learners it is essential to pay close attention to context. It’s not just about what to say, but also when to say it, with whom it is appropriate, and so on. You must understand why certain language is used in certain situations. Language and behavior in all communicative situations are governed by the following conditions:
- time
- place
- roles of the individuals involved
- script (which includes dialogue and actions)
- audience (those around not directly involved)
Our behavior certainly changes from the boardroom to the classroom to the street corner. Likewise the many roles we play in life will also determine our linguistic and social behavior—from student to employee to boss to friend, classmate, and so on. Even something as simple as a greeting must be contextualized. How you greet someone depends on where you are, when the greeting takes place, and your relationship with the person you are greeting. If you change one of these conditions, then the greeting will likely change as well. Greeting your teacher or your boss will be very different from greeting your roommate or your mother.
Into the Middle Kingdom 
I think you have hit the nail on the head with this post. The difficulty for the non-native is that it is very difficult to understand how each of the five conditions you mention should affect behavior and what the resulting behavior (culturally and linguistically) should be. On the other hand, the native unconsciously adapts to the conditions and is often unable to explain the how and whys to us non-natives.
I am still new to Chinese language, but Chinese culture has fascinated me since I was a child. I think this is always true of going to a new place (often times even if they speak the same language). It is very easy for cultural references to elude us. However, it seems where ever you go as long as you stay aware of your situation and always remain polite you will eventually understand cultural differences without insulting anyone.
I 100% agree with this article. Learning culture is very important. Learning language is also learning the culture. However, going to the country, meeting many different people, and learning the actual culture between people is more important!
I am glad you commented on how American sarcasm doesn’t translate well in Chinese. Luckily I didn’t have to experience this, but some of my peers got in trouble when trying to joke around with mainlanders only to be met with hostility. Having a strong understanding of Chinese culture is key to survival in China.
I like the analogy you used with the two sports. I agree that it is easy to forget that people from different countries have different social rules. I once hosted a forging exchange student, and she needed something like really late at night, so I told I would go to the store and get it for her, and she was surprised that there would still be a store open at this time of night. And another time we were at a restaurant, an ad like she couldn’t believe that we asked for to go boxes, and the waitress brought them. Learning the language is only the first step in learning how to communicate with people.
While I was expecting a crime report, this was an eye opening synopsis of situational awareness. While my Chinese is far from fluent, I will need to learn both formal and informal conversation styles. My teachers are very friendly, so most of my vocabulary feels a bit mixed regarding how formal/casual I might sound. In any case, I doubt I’ll be too dangerous in China; though I’m prepared to make a few embarrassing errors along the way