Of course, the Mucha Museum is not the only offender. Take a look around, and you'll find that this phenomenon is very common in the Czech Republic. Some of the other cases are equally unbelievable. I have seen concerts in Prague advertised in several languages on one flyer. The trick of using Czech language to hide their underhanded intentions is simply shameful.
Most hotels also have a dual price structure.
Another offender is the Jewish Museum in Josefov. A foreigner pays seven times as much for the same exhibition. I might add that in this case, such a sum for a museum is rather high even in Britain and America when converted to pounds and dollars. Some justify this stupidity by saying that all foreigners are rich anyway so it doesn't really matter to them. The reality is that ALL foreigners must pay more no matter where they are from.