They are shown without a role and their enrollment method is greyed out.
As is typical for the integrated automation between Banner and Moodle for registrations, it takes about 30 hours to update. However, the registration is forced in Moodle if the student accesses their course once they have registered in Banner. An instructor who wants to compare their current Banner roster with the latest student list in moodle should look at the Participants List, and not the Users List.
Both lists will fluctuate until drop/adds expires for that semester. However, be prepared to see some students still listed in your course's User List, as all students that register, whether or not they drop, will be listed there. They will be shown grayed out under the Enrollment methods column of the Users List. The Participants list, however, should only reflect your current attendees.
There are two lists within Moodle, "Users" which reflect all students that register (even those who then drop the course) and "Participants", a list that shows the current students registered for the course. This list is the list that will be reflected in your gradebook. Please remember that any student that registers should immediately access your course in Moodle. If they don't it will take about 30 hours to update their information on to your list.