Noctua is one of few companies that has not broken my trust (yet). They promise me a really good fan, they're ten toes in on the promise and they have yet to fail to deliver.
Though it's not that likely that users will try to replace the blades on a fan.
This was their response when I asked why: > Yes this policy was put in place because there was multiple instances of people reselling their faulty products after receiving a replacement.
> The secondhand buyers then reached out to us, let down to have received a broken product.
I'd imagine it's a similar reason for Noctua.