Why is a printed school directory more insecure than a mobile and online directory?

The print school directories is a valuable tool for parents who want to connect with other parents in their school community.  However, these print directories also represent a security risk since they can be readily transferred to anyone outside of the intended school community.  An extreme misuse of the directory and its contents is illustrated by an example of an ongoing online auction of school directory to the highest bidder. Please show your strong disapproval of this directory auction posting.  A collective request to remove this posting will prevent similar postings in the future.