Which effectively nobody does. Package managers and distribution packaging systems default to the safe method rather then defaulting to insecure rewritable tags.
To be fair, the docker.io/library/* images are signed but no other images are and there are a bunch of issues with how the signing policies work for users that want to enforce that some images must be signed.
To be fair, the docker.io/library/* images are signed but no other images are and there are a bunch of issues with how the signing policies work for users that want to enforce that some images must be signed.