http://www.linuxfromscratch.org/blfs/view/cvs/postlfs/devices.html
Apparently you may be able to add the user to the usb group to enable, but that is akin to giving the user 'root' group permissions, apparently.
from the link, above:
Fine-tuning of device attributes such as group name and permissions is
possible by creating extra udev rules, matching on something like
this. The vendor and product can be found by searching the
/sys/devices directory entries or using udevadm info after the device
has been attached. See the documentation in the current udev directory
of /usr/share/doc for details.
for example
SUBSYSTEM=="usb_device", SYSFS{idVendor}=="05d8", SYSFS{idProduct}=="4002", \
GROUP:="scanner", MODE:="0660"
'scanner' would be the group assigned to the item above. Again, according to the post, udevadm info
would give the vendo and product ids for above.