Above: The typical “big man” syndrome:
First he pushes through. This is enough to make most lower-ranking people in most circumstances humbly back off.
Secondly the physical contact from the screener enrages the big man who, in Thai-style, does not value physical touch (as opposed to international customs of hugging, and shaking hands).
Next the big man shakes his ID badge to indicate “do you know who I am?” This is done as a response to the perceived impertinence of a lower-ranking person who is not acceding to the higher rank of the superior person.
The ear slap is not typical, but physical striking can happen when one or the other Thai parties is highly agitated (i.e. “pushed too far” — when acting out is seen as an inevitable and logical response to events).
All the while the screener bows humbly again and again to express his deference and defuse the situation.
High Ranking Customs Official Physically Abuses Airport Security – thailandoutlook.tv, January 11, 2012