They come to the US with a clear intention to sell goods and services on the US soil. It looks like they'd be liable to pay taxes in the US. When you visit US you have to fill in the immigration form and there's a point where they ask you if you intend to sell goods and services during your trip. Seems like a grey zone to me. One call from a person unhappy with the 15k coat or 2x up charge to their representative and it might start a tax evasion investigation 🤷Most of the time they'll bill you later when they get home. You won't pay sales tax or VAT but you could be tagged with import taxes.