I fully understand why you would want to do this, but as a consumer I would never buy this product with this clause.
No. Everyone that builds projects inside someone else's ecosystem is subject to this. Even companies that like what your are doing might break it if they aren't specifically testing against your product.
For 10EUR, not only would I not worry about a refund but now I’m buying one or two to use myself on my bicycle and car.
Nobody has a right to a successful business but when consumers can trust their purchases they are more likely to make additional purchases.
> if it stops working.
It doesn't magically stop working though, it would be apple explicitly putting in effort to break this functionality and forcing you to update a device you own, forcing you to use it only how they want you to use it.
Or is that why the tag flashes and makes sounds frequently so that people without phones can know they’re being tracked?