I am running AT scheduled batch file backups in about 200 remote locations that have users that are… well, less than computer illiterate. <-- putting it nicely

Sometimes the users forget to change the tape, and I have it set to eject the tape at the end of the night before backup. If the backup tries to run and there is no tape, it hangs the system and the only way I can fix it is to reboot.

Is there an ntbackup switch or any other method I can implement that will NOT run the backup if there is NOT a tape in the drive?