Please explain how users shall gain permissions to burn CDs or DVDs.

1. 
$ l /usr/bin/cdrecord 
-rwxr-xr-x 1 root root 446200 29. Sep 00:59 /usr/bin/cdrecord*

2.
$ cdrecord -scanbus
Cdrecord-ProDVD-ProBD-Clone 3.01a24 (x86_64-unknown-linux-gnu) Copyright (C)
1995-2014 Joerg Schilling
cdrecord: Insufficient 'file read' privileges. You will not be able to open all
needed devices.
cdrecord: Insufficient 'file write' privileges. You will not be able to open
all needed devices.
cdrecord: Insufficient 'device' privileges. You may not be able to send all
needed SCSI commands, this my cause various unexplainable problems.
cdrecord: Insufficient 'network' privileges. You will not be able to do remote
SCSI.
cdrecord: Keine Berechtigung. Cannot open '/dev/sg0'. Cannot open or use SCSI
driver.
cdrecord: For possible targets try 'cdrecord -scanbus'. Make sure you are root.
cdrecord: For possible transport specifiers try 'cdrecord dev=help'.

3. Use the helpers from https://bugzilla.novell.com/show_bug.cgi?id=896601#c4

4.
$ l /usr/bin/cdrecord 
-rws--x--- 1 root cdrom 446200 29. Sep 00:59 /usr/bin/cdrecord*

5.
$ cdrecord -scanbus
Cdrecord-ProDVD-ProBD-Clone 3.01a24 (x86_64-unknown-linux-gnu) Copyright (C)
1995-2014 Joerg Schilling
Linux sg driver version: 3.5.36
Using libscg version 'schily-0.9'.
scsibus5:
        5,0,0   500) 'ATA     ' 'SAMSUNG SP0812C ' '0-25' Disk
        5,1,0   501) *
        5,2,0   502) *
        5,3,0   503) *
        5,4,0   504) *
        5,5,0   505) *
        5,6,0   506) *
        5,7,0   507) *
scsibus7:
        7,0,0   700) 'TSSTcorp' 'CDDVDW SH-S223C ' 'SB06' Removable CD-ROM
        7,1,0   701) *
        7,2,0   702) *
        7,3,0   703) *
        7,4,0   704) *
        7,5,0   705) *
        7,6,0   706) *
        7,7,0   707) *
scsibus9:
        9,0,0   900) 'ATA     ' 'Samsung SSD 840 ' 'BB0Q' Disk
        9,1,0   901) *
        9,2,0   902) *
        9,3,0   903) *
        9,4,0   904) *
        9,5,0   905) *
        9,6,0   906) *
        9,7,0   907) *
scsibus15:
        15,0,0  1500) 'Marvell ' 'Console         ' '1.01' Removable Processor
        15,1,0  1501) *
        15,2,0  1502) *
        15,3,0  1503) *
        15,4,0  1504) *
        15,5,0  1505) *
        15,6,0  1506) *
        15,7,0  1507) *
scsibus16:
        16,0,0  1600) '        ' '                ' '8.07' Removable Disk
        16,1,0  1601) *
        16,2,0  1602) *
        16,3,0  1603) *
        16,4,0  1604) *
        16,5,0  1605) *
        16,6,0  1606) *
        16,7,0  1607) *