Oh, I completely forgot about recurring events. Let me think about how to add it to the NIP.
Discussion
This, if done wrong, will render it a source of endless misery for generations
so no pressure 😹⚡🤙💜
When you introduce recurring events, you also need to handle cancellations of instances, cancellations of ranges of instances, and modifications to instances. The problem with rhe vcard specification is this aspect seems to be ambiguous enough to have caused confusion across implementations.
Im not proposing you add recurances, only that it should be addressed. You might decide to simply specify there are no recurring event types and all calendar events must be specified as separate objects.