If a Choice activity is configured for "Separate groups" or "Visible groups" and user is enrolled in course but is not a member of any group, I would like to have the option to configure the Choice activity to prevent the user from making a choice.

I would like to use this to limit which students can make choices for an upcoming event. Many students will be enrolled in the course. As student submit required paperwork, they will be added to a group. (Until the paperwork is in, the student is enrolled but is not a member of the group.) Members of the group can make selections (bus assignment, hotel room, activities, etc), and those not in the "paperwork completed" group can't make any choices.