That is an interpretation of the law and is not in accord with what the ICO (the regulator) is saying. If you have a site called "UK Expats" and you block EU IPs you will still be liable since your site is offering a service to EU citizens. A less extreme use case but equally applicable, you have a shoe store in the US and your style is liked by french citizens living in the US, since a considerable amount of traffic is coming from EU citizens you are under GDPR. even if it is only 20%, even if they are in the US, even if you blocked all European IPs