We had an individual in our organization that used to handle conference
room scheduling. The user has since been moved to another position, and
thus their permissions to schedule appointments for those resources
were taken away. However, they are still able to schedule appointments
for some reason. If the permissions were functioning correctly, they
would just be a reviewer. I have a separate security group set up that
has permissions to do scheduling, but the user in question is not a
member of that group. Is there some reason why a person would still be
able to schedule appointments, even after their permissions have been
taken away?

Problem solved-- turns out the user only locks their machine at night
instead of logging out. A reboot/re-logon allowed the new permissions
to take effect and now they are unable to schedule meetings. Hope this
helps someone...