/lib/udev/rules.d is meant as an upstream source and should not be touched. If you want to override a rules file, copy it to /etc/udev/rules.d and edit it there. From CHANGES_AND_HINTS.TXT:
Code:
As with 13.37, the system udev rules now reside in /lib/udev/rules.d/ instead
of /etc/udev/rules.d/ in older versions. There should never be a reason
to edit anything in /lib/udev/rules.d/, so if you think you have a case
where this is required, either you're wrong or it needs to be addressed in
the upstream source. However, you can override default rules by placing
one with an identical name inside /etc/udev/rules.d/ The rules files in
/etc/udev/rules.d/ are still intended to (maybe) be edited as needed by
local system administrators, and as such, the rules for optical and network
devices will still be placed there.