I think udev.conf should be. It is part of the "kernel- udev-rules" dynamic maintenance system. TC too should have some sort of state-machine to maintain udev rules consistency. And the base point of that state-machine is probably "udev.conf". It is NOT a proper attitude to leave everything as default, udev rules is must live dynamically.
When user makes modifications to this "udev.conf" file, it is safe to overrule these modifications by system if needed. For example, LinuxUnifiedDriver try to install 98 and 99 level of sane rules which is not healthy.
I suspect, that these Xorg/sane installation mess is the result for that kernel-udev-rules ignoring.