[bouncycastle]

Anti-fraud may been the reason on that day, but who knows what will be the reason tomorrow (eg Capital Controls as it happened in Greece). The main point is that I still had to get permission. It's kind of like when I was a kid, I wasn't allowed to go outside the house unless I informed my parents, which was like getting permission implicitly.

When using cash, you do not have to inform the bank anything.

[XorNot]

No you have to visit a money exchanger in advance, exchange some money into local currency, then go to your destination.

Which...is the same thing you need to do anyway to use your card in China.

[uiri]

If you're in the US or Europe, you'll probably get a better rate by exchanging cash into local currency at your destination.

[lorenzhs]

For me, it’s always been cheapest to use an ATM at my destination, and let my bank do the currency conversion instead of using the rate offered by the ATM. My bank charges me something like max(5€, 1%), which is usually substantially cheaper than all the other options. I think this is more or less the same (or cheaper) for all German banks.

[rahimnathwani]

Almost all UK banks charge 2.75% above the visa/mc wholesale rate for overseas transactions. Plus they usually charge 1%-1.5% for overseas ATM transactions.

This is so prevalent that it's common for new banks (or existing banks doing a push for their new current account) to offer commission-free overseas spending. But many of them have pulled the 'perk' after they've gained a large enough customer base. If I recall correctly, at least Halifax, Nationwide and Metro Bank have in the past offered accounts with no commission on overseas card transactions, and then changed the terms to the standard (2.25%-2.75%) after 1-3 years.