Here is a scenario where you have Windows users who need to log into an encrypted directory that is mounted on a Linux Samba share. This provides an interesting option for security.
The Linux user, who has sudo access logins in and when they do login are asked to mount the truecrypt volume and also restart samba server because the volume will exist on a Samba share. It is imperative that the user who mounts the share is in the adm group so they are able to enter the sudo commands to run programs as root.