I have a headless Ubuntu server running v10.10 plus 2 cameras.
Motion runs OK from the command line with 2 cameras.  It crashes when started as a daemon process.

When run from the command line, it is run as user <me>.  When run as a daemon process it is run as user <motion>. 
<me> is a member of<motion> group so it shouldn't matter.  Motion also runs OK from the command line with <sudo>.  I am just pointing this out because it is the only obvious difference between running from the CLI and running a daemon process.


Output from my syslog is below:

Jan 17 23:10:49 alpha motion: [0] Processing thread 0 - config file /etc/motion/motion.conf
Jan 17 23:10:49 alpha motion: [0] Processing config file /etc/motion/trackcam1.conf
Jan 17 23:10:49 alpha motion: [0] Processing config file /etc/motion/trackcam2.conf
Jan 17 23:10:49 alpha motion: [0] Motion 3.2.12 Started
Jan 17 23:10:49 alpha motion: [0] Created process id file /var/run/motion/motion.pid. Process ID is 5440
Jan 17 23:10:49 alpha motion: [0] Motion running as daemon process
Jan 17 23:10:49 alpha motion: [0] ffmpeg LIBAVCODEC_BUILD 3482112 LIBAVFORMAT_BUILD 3478528
Jan 17 23:10:49 alpha motion: [0] Thread 1 is from /etc/motion/trackcam1.conf
Jan 17 23:10:49 alpha motion: [0] Thread 2 is from /etc/motion/trackcam2.conf
Jan 17 23:10:49 alpha motion: [2] Thread 2 started
Jan 17 23:10:49 alpha motion: [2] cap.driver: "uvcvideo"
Jan 17 23:10:49 alpha motion: [2] cap.card: "UVC Camera (046d:0807)"
Jan 17 23:10:49 alpha motion: [2] cap.bus_info: "usb-0000:01:07.0-1"
Jan 17 23:10:49 alpha motion: [2] cap.capabilities=0x04000001
Jan 17 23:10:49 alpha motion: [1] Thread 1 started
Jan 17 23:10:49 alpha motion: [2] - VIDEO_CAPTURE
Jan 17 23:10:49 alpha motion: [2] - STREAMING
Jan 17 23:10:49 alpha motion: [2] Test palette MJPG (960x720)
Jan 17 23:10:49 alpha motion: [2] Adjusting resolution from 960x720 to 800x600.
Jan 17 23:10:49 alpha motion: [2] Using palette MJPG (800x600) bytesperlines 0 sizeimage 62933 colorspace 00000008
Jan 17 23:10:49 alpha motion: [2] found control 0x00980900, "Brightness", range 0,255 
Jan 17 23:10:49 alpha motion: [2] #011"Brightness", default 128, current 128
Jan 17 23:10:49 alpha motion: [2] found control 0x00980901, "Contrast", range 0,255 
Jan 17 23:10:49 alpha motion: [2] #011"Contrast", default 32, current 32
Jan 17 23:10:49 alpha motion: [2] found control 0x00980902, "Saturation", range 0,255 
Jan 17 23:10:49 alpha motion: [2] #011"Saturation", default 31, current 31
Jan 17 23:10:49 alpha motion: [2] found control 0x00980913, "Gain", range 0,255 
Jan 17 23:10:49 alpha motion: [2] #011"Gain", default 0, current 48
Jan 17 23:10:49 alpha motion: [2] mmap information:
Jan 17 23:10:49 alpha motion: [2] frames=4
Jan 17 23:10:49 alpha motion: [2] 0 length=62933
Jan 17 23:10:49 alpha motion: [2] 1 length=62933
Jan 17 23:10:49 alpha motion: [2] 2 length=62933
Jan 17 23:10:49 alpha motion: [2] 3 length=62933
Jan 17 23:10:49 alpha motion: [1] cap.driver: "uvcvideo"
Jan 17 23:10:49 alpha motion: [1] cap.card: "UVC Camera (046d:0807)"
Jan 17 23:10:49 alpha motion: [1] cap.bus_info: "usb-0000:01:07.3-2"
Jan 17 23:10:49 alpha motion: [1] cap.capabilities=0x04000001
Jan 17 23:10:49 alpha motion: [1] - VIDEO_CAPTURE
Jan 17 23:10:49 alpha motion: [1] - STREAMING
Jan 17 23:10:49 alpha motion: [2] Resizing pre_capture buffer to 1 items
Jan 17 23:10:49 alpha motion: [1] Test palette MJPG (960x720)
Jan 17 23:10:49 alpha motion: [1] Using palette MJPG (960x720) bytesperlines 0 sizeimage 682666 colorspace 00000008
Jan 17 23:10:49 alpha motion: [1] found control 0x00980900, "Brightness", range 0,255 
Jan 17 23:10:49 alpha motion: [1] #011"Brightness", default 128, current 128
Jan 17 23:10:49 alpha motion: [1] found control 0x00980901, "Contrast", range 0,255 
Jan 17 23:10:49 alpha motion: [1] #011"Contrast", default 32, current 32
Jan 17 23:10:49 alpha motion: [1] found control 0x00980902, "Saturation", range 0,255 
Jan 17 23:10:49 alpha motion: [1] #011"Saturation", default 31, current 31
Jan 17 23:10:49 alpha motion: [1] found control 0x00980913, "Gain", range 0,255 
Jan 17 23:10:49 alpha motion: [1] #011"Gain", default 0, current 48
Jan 17 23:10:49 alpha motion: [1] mmap information:
Jan 17 23:10:49 alpha motion: [1] frames=4
Jan 17 23:10:49 alpha motion: [1] 0 length=682666
Jan 17 23:10:49 alpha motion: [1] 1 length=682666
Jan 17 23:10:49 alpha motion: [1] 2 length=682666
Jan 17 23:10:49 alpha motion: [1] 3 length=682666
Jan 17 23:10:49 alpha motion: [1] Resizing pre_capture buffer to 1 items
Jan 17 23:10:50 alpha motion: [2] Resizing pre_capture buffer to 3 items
Jan 17 23:10:50 alpha motion: [1] Resizing pre_capture buffer to 3 items
Jan 17 23:10:50 alpha kernel: [180384.787640] motion[5442]: segfault at b443a138 ip 00a570a7 sp b6fb8a20 error 4 in libjpeg.so.62.0.0[a53000+22000]