@ Farmer:
No one is suggesting for a minute that a business be forced to sell to anybody. The issue here is that many suppliers happily sell all round the world, all manner of products. We buy inks for one Canon iPF from the US, Hong Kong, China and wherever we can get a better price than locally in Oz. They all work well and we only buy genuine Canon product for our main machine. (A Canon reseller here who has been trying to get Canon to reduce its eye-watering price with no success, tells us how to be sure of the product.)
In another machine we use InkJet Carts ink from the US with no premature head failures or even color issues. We went this way after several contacts in the advertising print business told us that that industry isn't negative at all about third-party inks, many use them. The savings on these carts is such that if heads only last half the usual time, we're ahead on overall costs - they last much longer than half actually.
I fully realize that others have a completely different view about all this and I value any input, it's an interesting topic.