If a player joins one of my events, are they automatically added to my group?

Yes —By default, your group’s setting is toggled on so that “Users who join group events automatically become group members”.

If you want to change that setting, Go to your Group > Click the “Settings” Tab > Under “Group Permissions”, Select the setting

Change your group settings through the web or app.

How it looks for a player who joins your event:

Web view:

Web view: When a player joins your public event, they see a message saying: “Joining this event adds you to the group”

App view:

App view: When a player joins your public event, they see a message saying: “Joining this event adds you to the group”