VAT Exemption Module v2.3.0 - customers can abuse the system

[30knees]

The VAT exemption module drops VAT based on the billing address only. Can it take the shipping address into consideration, too?

Problem: For an EU-located store, a customer can add a (real or fake) billing address in Switzerland, a shipping address in Germany, and then get the order without VAT.

This is a problem because in that scenario the customer would actually need to present the invoice to customs when crossing the border from Germany to Switzerland, get the invoice stamped, and send the shop a copy. Otherwise, the shop will be liable for the VAT that wasn't collected.

Proposal: If the shipping address is NOT in a country where VAT shouldn't be charged, the order should always include VAT.

If a customer presents a stamped invoice the shop can still refund the VAT.