I bought some security software online recently. When the "pay" screen came up, it had automatically added Irish VAT @ 23% to the invoice. So I cancelled the transaction and closed the window. I then used my VPN to locate myself in Andorra (VAT in Andorra is 2.5%) and then proceeded to purchase the software. The purchase involved me being emailed a licence number for the software, so nothing physical occurred.
My saving was less than €8, and, as Andorra is in the EU, it was legal, but the point is that if an old codger like me can do that, then I'm pretty sure that smart people will be able to bypass your financial transaction levy!