David Broadfoot And the Franks are the ancestors of the French. Your point makes sense because when the French embassy came to the king Narai, there was an influent Persian community in Ayuthaya. They probably told the Thai elite that those white people where Faranghi.
True for the majority, but not always. I was once at the Malaysian border Thai checkpoint. I asked the immigration officer in Thai for a TM entry card, she replied "Thai nationals don't need them anymore". Oh God I felt proud 😍.
Farang is the alteration of Farangset, Thai pronunciation for "Français" which means French in French language. The first Whites staying in the kingdom where people sent by king Louis 14th to king Narai. In Khmer it's Barang because they don't have the F sound. In Laos, Farang simply means France.
ie People who shared their experience on Facebook groups. I can't speak about the silent ones, that's why I can't say if the insurance was requested to all non-O or not.
"Note: Although International Driving Licences are valid for up to one year after arrival in Thailand, after three months many comprehensive insurance policies are made void if still driving on a foreign licence."
"The licence needs to have been issued by a country that has a treaty with the Thai government allowing the mutual acceptance of driving licences. Most countries, including Australia, Canada, New Zealand, the UK and the USA have this agreement with Thailand".