PAY MORE IF YOU'RE NOT THAI

Earlier this week Thailand's Department of National Parks, Wildlife and Parks announced a new list of entrance charges for the Kingdom's National Parks. At some parks it will cost 40 baht to enter if you're Thai but 400 baht if you're a foreigner. http://www.dnp.go.th/parkreserve/np_rate.asp?lg=2
Anyone who has lived in Thailand for any length of time will know that double pricing (although this is more than double) is common. I've personally seen the signs at public toilets and some temples which have the lower Thai price written in Thai script and the inflated foreign price in English. That's just pure deception.
But having a different pricing structure for visitors isn't unique to Thailand. I think in parts of the US you get a reduce rate admission to certain attractions if you live in the same state. However, can anyone justify charging visitors up to ten times more than locals, especially in a country that relies so heavily on its income from tourism?