It looks rather like a BS546 plug, but with the line and neutral pins closer to CEE 7/7 layout. It looks a bit like BS546 5Amp, or the Danish 'smiley face' plug system :
http://farm3.static.flickr.com/2170/2176018145_1789632d24.jpg?v=0 I don't know why Thailand wouldn't have just adopted CEE 7/7, using the French socket if polarisation was a concern. It's the de facto standard for 230V 50Hz.
I'm not a fan of having umpteen different pin layouts co-existing with multi-standard socket outlets. It invariably ends up with weird adapters.
All this will achieve is CEE 7/7 (schuko) plugs plugged in to outlets without the grounding system making contact with anything. Similar to Denmark's current situation.
Also, 110V plugs i.e. NEMA 1-15 & 5-15 etc shouldn't really be used with anything other than 110V appliances as there's always a risk that someone will accidentally connect a North American or Japanese specified appliance to a 230V circuit and end up with smoke and fireworks. I have never understood why they are used by certain countries in the Far East, including China with 220-230V gear.
