Manage user rights per plan as available to outlook folders as a whole allowing archiving
Running planner as an integral part of project operation for e.g. consulting companies would make it necessary to archive and therefore manage rights distinct from actual users working on a plan.
E.g. a plan is completed, does have documentation assigned to it, run by freelancers. The plan needs to be archived, freelancer access rights need to be removed, but legal or intellectual property departments still need to have access.