Processing my personal data in such a way (to ban me from your services pre-emptively) would be a breach of the GDPR and in some member states could involve criminal sanctions.

For example, in the UK we have a very famous case (The Consulting Association (TCA)) where building contractors joined together to build a list of construction workers they didn't want to hire - this was determined as a criminal breach of UK data protection law.

So have at it, I love a challenge...