I've experienced and heard about many situations where a CC email is forwarded to a group as an fyi, and then someone in that forwarded group clicks unsubscribe, which removes the original CC member. Then to make matters worse, apparently an antispam protocol is initiated whereby the original email address can't get emails again. This is a major flaw! The unsubscribe request should ALWAYS be confirmed via an email from CC to the address requesting the unsubscribe. fyi a couple groups that I belong to that use CC are thinking of moving to a different platform, largely due to this.