It may be semantics, but an important distinction, but it's a reprice, not a rebook.
If you mention the word "rebook" to an RC agent you might find you have rebooking fees.
A reprice is free.
Norovirus is one of the most contagious viruses out there. Airborne, droplets, contact, etc.
When it hits, it hits. And it has hit a lot more post-covid (not just cruise ships, but everywhere) than it did before.
Seeing as the number of first time cruisers who want to take a second cruise is higher now than it was before covid, I'd say just about every passenger is happy.
Even those that have a terrible time seem to enjoy finding ways that it was terrible.