Mrs. Majuki made two purchases at a department store in Kaohsiung, one at Muji and one at Uniqlo. I saw that they had two credit card payment terminals, but the cashiers at both stores used the National Credit Card Center ones, which presented a DCC prompt for both transactions (with a tap). At Muji, the cashier verbally proactively offered, "台幣 (táibì)," which we could select as the number 2 option on the screen. Like the purchase more than a month ago, the signature slip appears on the terminal with the total in the selected currency. I suppose in the case of a forced DCC you could refuse to sign at that point, but it hasn't been an issue. Even in cases where the terminals are not customer facing, the cashier has always presented the terminal at retail shops or respected the currency choice at hotels.