at least make it visible: in a lot of cases, people will understand the difference in price if it is to do with encouraging certain groups of people to visit. An aside note- as a European who was an exchange student Thailand, I often received the Thai pricing (I could read the Thai) at various locations if I showed my student card from my Thai university. And, I’ve been to Oasis Sea World- I don’t think it is really worth it if you have to pay full foreigner price.