Description of problem:

Tried to burn cd as a normal user and k3b did not have write 
access to /dev/sr0

Version-Release number of selected component (if applicable):

udev-124-1.fc9.1.x86_64

How reproducible:

Always

Steps to Reproduce:
1. Insert a cd to burn
2.
3.
  
Actual results:

k3b did not have write access to /dev/sr0

Expected results:

k3b to have write access to /dev/sr0

Additional info:

Adding the user to the group disk
Then changing MODE from 0640 to 0660 in line 61 in  
/etc/udev/rules.d/50-udev-default.rules
( SUBSYSTEM=="block", GROUP="disk", MODE="0660" )

Restarting udev fixes this issue.

I do believe users should be added by default to the disk group as well.