How do they keep track of who you are? I presume you need a VAT ID of some form? (From https://en.wikipedia.org/wiki/VAT_identification_number#VAT_numbers_of_no

How do they keep track of who you are? I presume you need a VAT ID of some form? (From https://en.wikipedia.org/wiki/VAT_identification_number#VAT_numbers_of_non-EU_countries https://en.wikipedia.org/wiki/VAT_identification_number#VAT_..., it looks like they’ve crafted it so that many countries’ business numbers can be turned into VAT IDs painlessly, e.g. Canada’s work direct, Australia’s you prefix with a two-digit checksum. I note the conspicuous absence of the USA from the list. I have no idea about US tax.)