A week ago a woman staying at a small resort near are house was arrested for overstaying 2 days. We saw the police there and asked our village chief and got the details. Very bad situation.
for long term visas proof of onward travel is not required. This was explained to me by Thai immigration. Visa exempt or tourist visas it is required. this is the law.
First of all the Embassy websites are often wrong as the UK one says you do need an IDP. Technically you do not need an International Driving Permit if your home country licence has a photo and is in English. However, in reality, you will need one as the police use it as an excuse to fine you and insurance companies use it as an excuse not to pay your claim. But this is only if you are a tourist. less than 90 days