If a user belongs to more than one group, sometimes the permissions inherited from those groups may conflict.
For example, one group's members may have permission to modify topics whose release state is "Final" or "First Draft", and another group's members may have permission to modify only "First Draft" topics but not "Final" ones.
When there is such a conflict of inherited permissions, the least restrictive permission is used, which in this example is the ability to modify both "Final" and "First Draft" topics.