With Mallard, a course director can "lock out" individual users or all users with a given access level. For instance, students could be blocked from accessing their Mallard course materials until after the first lecture. A student might be locked out if he has not yet paid his course fees. When a user's account is blocked, he will see whatever message was specified by the course director.

It is also possible to lock out all instructors and/or developers, and to have distinct messages for different levels of users.