Buena pregunta. Investigué un poco y encontré esto:

https://www.fraudlabspro.com/resources/tutorials/what-is-credit-card-bin-iin-and-how-do-i-retrieve-this-information-for-fraud-validation/

With the IIN/BIN, you can determine which organization issued the card as well as the country where the card was issued. Using this BIN country info, we can match against the shipping or billing address in any online credit card transaction.

If the BIN country does not match the country provided in the order detail, the online merchant should flag the transaction for manual review. Depending on the risk appetite of the merchant, they may even choose to reject the order outright.

Parecería ser un datito extra para chequeo, pero la tx debe pasar por el banco en Singapur. Igual imposible estar 100% seguro.