Further, there is nothing that prevents you from creating (or changing) the "secret" after the blockchain ID is generated.
Maybe you need to actually read the page that DirectBet linked you to:
Obviously we can not reveal the secret before the deck is shuffled because this will allow you to know in advance the outcome of the game. Therefore, we scramble the secret in a special technique called hashing using SHA256 cryptographic algorithm and present the hashed secret in the Bet Status page. The only way to reproduce the hashed secret is by hashing the original secret. Later on, after the game is over, we will reveal the original secret used, and you will be able to hash it yourself and verify that the result is identical to the hashed secret presented to you before the game. This will prove that we did indeed used the secret that was designated to your bet.
maybe you need to realize that none of us have any idea what goes on behind the scenes at directbet. there is NOTHING that prevents them from altering the hidden secret.