Well, I am trying to fully understand what the EU law requires, and for this reason do not take my assumptions as totally correct.
In practice, I think that the user registration process involves privacy acceptance, whereas the simple website visit only requires cookie acceptance or refusal.
Take for instance how C.B. works (I do not know if I can write the full name as it is a commercial service…). On website visit it gives you the possibility of accepting or refusing cookies classified by category (required, web analytics, marketing…). No acceptance on privacy at simple site visit stage.
Therefore I think that the best solution would be the possibility of accepting each single option at site view or at user registration, or both. This would give us the chance of limiting privacy acceptance on user registration only.
Thank you!