I wasn't involved in the Dutch registry. In the Netherlands, the medical specialists affirmed the starting of the registry and then patients were invited to pay for it. That's mandatory. They do not opt out, but also, if they opt out, they still have to pay the $40 extra. Of course, for patients with cancer, it's reimbursed by health insurance, and for those patients who do it with cosmetic, it's not.
On May 9th, 2023. See this statement in context.