Even Amazon will let you get pretty far before it tells you that product is not allowed for sale in your region. Worst case was a big ticket ASUS laptop I did plenty of research on (there may be warnings on the product pages IF you are logged in while browsing, I was not).
>there may be warnings on the product pages [about regional availability]* IF you are logged in while browsing,*
This is the right way to do it. How're they supposed to know where you're from, where you'll be buying, if you're not logged in. The alternative appears to be to ask every visitor to give their location before you show them anything.
They're not very accurate. They get my country wrong quite regularly.
Also Amazon may know your current location but not where you'll be when you buy something. If I'm travelling does that mean that I can't buy something shipped to my home that would I could buy if I were at home.
Amazon tends to just mention that the item is not available to shipping for all countries and only at checkout does it complain that it may not sell it to you.
To add insult to injury they now spam me advertisements of the products I had to abandon, which they naturally still cannot sell me.