Do you have documentation somewhere to support that?  (I don't doubt you, but it'd be nice to link to the documentation in any further edits of that code)

I only have a quick answer right now: run for example 

$ udevadm info --query=all --name=/dev/sda

I didn't do extensive research; just trying to figure out why F17 preupgrade fails with a disk that contains guid partition table :)

This was fixed before the Fedora 18 Alpha.