This deception is not only unique to Korea.

Chinese are very good at the we can't pay you more gambit.

I have just turned down an offer with a middle school in China because they only wanted to pay 65 rmb per hour for extra classes. As that is less than the minimum wage in the UK, I don't feel a foreign teacher (with experience!) should accept that amount. A GW would on the grounds that china is a "developing country" and just to sucker up to their boss, but not me!