You thought Korean hotels were any better than Chinese one? Me too. It's wrong.
So a few months ago, Chinese luxury hotels were caught using the same toilet brush to clean cups as well.
Now Korean hotels were caught, too. Again, luxury hotels in Seoul. Their average daily rates are easily over $200. At least Chinese hotels were in Harbin, where Kempinski (one of the caught hotel) cost about $77 on random date in March. On the same date, "S" hotel costs $250.
So it's not about the price you pay. Even if you pay over $200 in Seoul you'll still end up drinking water from sewage cup.