Foreigners have been known to complain that there are no rules in Thai society. People just seem to do what they feel like, or at least what they think they can get away with.

Nothing could be further from the truth. Thai life is replete with rules and regulations. Start with the constitution, one of the longest in the world, prescribing in minute detail things like the electoral process, and work your way down to the civil service regulations for the lowest-level functionaries (a compendious volume that no one could possible ever remember, let alone operate by). And you find that Thai rules rule.

But these are the formal rules, normally ignored when they are not flouted. They do exist and can be invoked, as you will find out if anyone in authority ever wants to make life difficult for you. But there is also a parallel set of rules that Thai people actually live by. The problem is that these rules, besides being unwritten, are also famously intricate.

Consider, for example, the complexity of figuring out the rules of social interaction that will decide how you refer to yourself in conversation. In English, a simple rule of grammar tells you to say ‘I’. In Thai, the sociolinguistic options (since they include proper names) are virtually countless.

But do not lose heart. A mere two or three decades of dedicated study will help you achieve enough understanding to negotiate most social situations without debasing yourself, abusing your interlocutor, or committing lèse majesté.

However, time and technology bring changes and the structure of Thai rules must adapt. So the learning task is never-ending. Take, for example, the recent case involving an under-age driver from a well-connected family involved in a tragic traffic accident. This incident has revealed some of the more subtle changes in the rules involved in such cases.

Children of the elite can, as before, continue to violate the formal rules by driving without a licence or insurance, can casually lend cars to each other (as a statement of status or a potential weapon, as well as a means of transportation) and have no more need to drive in a safe manner than the average driver of the tour bus to Yasothon. They can expect to do this with impunity, even if this has to be achieved via spurious claims of mental ill-health and endless legal manoeuvrings that exhaust the patience and resources of their victims. This much is well established.

But they must now expect to have their identity illegally exposed by the police and media; they must expect intruders into their hospital rooms; and they should realize that they will become the target of campaigns of vilification on the internet.

The police will continue to obey the rule of bending to the will of the highest bidder, but at a time when the relative strength of different factions is difficult to gauge, they will have to show unaccustomed restraint until the dominant power can be identified. This implies, among other things, ignoring blatant examples of hate speech.

And the middle classes, defined as those with enough spare time and cash to spend on social network sites but not sufficient wherewithal to indulge in their own high-speed accidents, have discovered that internet anonymity suspends many of the rules that previously cramped their style. They are now allowed to threaten strangers with death, violence and rape, to divulge their personal details over the internet, to fabricate supposedly incriminating evidence, to incite each other to violence, and to feel collectively self-righteous about doing all this.

Should any neutral observer question whether such behaviour is wise, moral or even sensible, they can still play the education card. By a long-standing rule of Thai society, it is assumed that the person who has had the longest education automatically has the highest moral character.

So if you dare to criticize the twitter vigilantes, they will just scream Facebook obscenities back at you, you ‘uneducate’ person.