I just confirmed with Engineering the behavior of the unsubscribe button for Scheduled Workspace project emails. The link will unsubscribe the single email recipient. It does not cancel the schedule, and it does not unsubscribe the entire recipient list.
If you are not seeing this behavior, please file a ticket with Customer Care to have it looked into further.
To further elaborate, instead of sending the scheduled report to an email distribution list, a more effective way would be to enter the email addresses inside of Adobe Analytics. That way, when an individual user unsubscribes, they unsubscribe themselves instead of the entire DL.