When Shuffl is in a Slack channel, it shuffls only people in the channel AND those who are opted-in!
People can change their opt status easily by themselves via: https://learn.shuffl.ai/en/articles/5053847-opt-in-out-of-a-shuffl-channel
Or you (as a Shuffl Admin) can toggle people's opt status in the Channel Members page within our Portal App! https://learn.shuffl.ai/en/articles/5235243-channel-members
Let us know if you have any questions!