The prohibition is 'except where allowed by treaty' etc and the Bowring Treaty allowed for British enjoyment of property rights etc on a par with Thais.

I have no doubt this treaty is ineffective now but can anyone point me to the lack of renewal / act abolishing it or whatever that made it ineffective - just out of historical interest?

Many thanks.

http://www.thailawforum.com/articles/reformation2.html#14

The Bowring treaty was a factor in why Thailand was not colonised.