Brief reports from a few places I visited in December/January:

Singapore: no problems except in one small self-service restaurant. The owner insisted that he hadn't chosen DCC and I'm happy to believe that he didn't do so knowingly, as he spent 20 minutes on the phone getting the transaction reversed while we ate.

Malaysia: no problems once I remembered to specify Ringgit when handing over my card.

Taiwan: one restaurant charge went through in USD despite my choice of TWD being clear. I disputed the difference (approx. 5 USD) and Chase credited my account within minutes.

S. Korea: a supermarket terminal gave me a clear choice, complete with coloured flags, and a tiny restaurant processed my payment in Won without any questions (and without a signature).^