## Rejection of CDs of other users

In environments where you don't have direct control over the network CD writer it can happen that

- someone else puts in a CD while webCDwriter is waiting for your CD
- someone closes the tray with your CD just burned while webCDwriter is waiting for the CD of the next user

To avoid at least the mixing of private data of two users on one CD webCDwriter writes a user ID to the "preparer ID" field of the ISO9660 filesystem. Before writing to a medium webCDwriter looks for a user ID and asks you, if this ID does not match yours.