Why publishing a hash before kick-off matters

A cryptographic hash is a fingerprint of a piece of text. Publishing the fingerprint of a selection before the event fixes that selection without revealing it, and publishing the text afterwards lets anybody confirm the two match.

It removes the one thing that cannot otherwise be checked. Every published record depends on the publisher not having changed anything after the fact, and normally there is no way to verify that from outside.

It says nothing about quality. A commitment scheme proves a pick was not altered; it does not make the pick good, and a service that implies otherwise is overselling its own mechanism.

The problem arrives next. It is easy to describe and easy to fake in appearance. A hash published without the reveal, or with a reveal that nobody can recompute, looks identical and establishes nothing.

What to do with it. Check that the reveal includes the salt, and recompute one hash yourself before believing any of the others.