They have been increasingly blocking purchase of digital content (Kindle books, Audible etc) based on geographic region anyway to the point that the advantage of being an international/.com customer was getting smaller.

It annoys the crap out of me that content can be available in one region and not another, I want to consume it and happy to pay for it.

This sounds like a publicity stunt. I mean, really, how hard is

    if (shipping_address[end-9:end] == "Australia")
    then
        pay_gst()
    else
        evade_sales_tax()
    end

They provided direct access to australians while destroying the local bookseller industry. Now they don't have to compete I think you'll find it is:

    if (shipping_address[end-9:end] == "Australia")
    then
        charge_australia_tax()
    end

https://en.wikipedia.org/wiki/Australia_Tax

The reasoning I suspect is more to do with price differentiation. It is easy to charge more to Australian consumers and I bet this is a business/commercial decision on Amazon's part more than it is to do with the technicalities of their back end.

By blocking the other Amazon websites its easier to force Australians to pay more for their shopping on Amazon for the same products on their US Store (even with GST + Shipping).

1. Where should this if statement live?

2. Your solution assumes the full shipping address is known to where you think this code should live.

3. No edge cases are being handled here.

4. What's the additional server burden for your solution? Do we need to provision additional capacity? What about DB capacity?

5. What does pay_gst actually do? Is it handling only charging an additional price? What about accounting, tax, and reporting?

6. Why are we evading sales tax in the else? We might still need to collect other sales taxes. Amazon.com is also the primary portal for NA, so it still needs to collect local/state taxes.

7. How should we handle updating the DB tables? What about the derived tables?

I could easily go on.

Even if the implementation is easy, the accounting will be a pain.

Use a remailing service like shipitto to get around it.

If they start rejecting aus credit cards, get use a pre paid visa card. Use a VPN if they geoblock the website.

thats way too much effort just to buy in amazon

The funny thing is that Amazon does the opposite for its sellers. The will offer different terms for different areas, the just order from the area with the terms that are most in their favor.