Discord has ephemeral messages for specific actions that only the person doing that action can see.

Having a similar system for users redeeming rewards would prevent the chat from spamming with the rewards where no one can now chat, but would also allow viewers to notice that rewards have been redeemed.

Additionally, these messages could also be sent back to a user when a channel point reward is marked as unfulfilled. This would allow services using the API to send a message along when they are unable to fulfill the reward.

An example of a rejection message with Crowd Control would be when a streamer sets a reward to a Crowd Control effect, in this example "Restart Level".

If a user redeems the Channel Reward "Restart Level", it says so in chat, but when it is rejected they have no info as to why it was rejected. So the service could send back the message which would only be visible to the redeemer.

This allows 3rd parties to introduce additional types of cooldowns and features on the rewards outside of the Twitch settings that could be more customizable.

Right now if a channel reward is automatically rejected the user can just keep redeeming it, again, and again as their channel points are returned, spamming chat with the redeem message and not knowing why they are being rejected/returned. Ephemeral or redeemer-only messages would prevent spaming chat.