The validation url you passed is the EU comm, not Arrow's. Where do you get the sentiment that they validate this on the Arrow checkout? Is this the site they forwarded you too?
I should have been more verbose about that. What I was trying to convey is that they do not merely check the VAT ID format as you suggested in your first answer, but actually check the number online with an API to the EU VAT inquiry system. The link I provided should merely demonstrate that checking the number for validity is dead simple and taps into the very same API.
The truth is probably in user
wrapers answer: They don't want to deal with the VAT hassle, their DDP process merely handles the tariffs, not VAT.
This is a bad decision an Arrows part. We have VAT exemption rules for small businesses in many European companies. They are now cut off from Arrow.
Personally, I find it very regrettable. Arrow was one of the few - if not the only - company that offered free shipping and had nearly no MOQ with few exceptions like mechanical parts. They only charged shipping for parts that shipped from their Japanese warehouse. And they were considerately cheaper compared to the big three. Simple bird food SMT parts are often three times more expensive.
My €28 BOM at Arrow costs €51 at Mouser and then they slap €20 shipping fee on it. Yeah, thanks.
Outside of my day job as an EE, I make small runs of boards for educational purposes for the local school. They have workgroups for kids that want to learn about electronics. Budgets are small, so this will kill that off or limit the possibilities to meddling with Arduinos.
Before anyone asks: The possibility to order this through the school is next to impossible due to red tape.