Comment 7 for bug 968074

@ Steve Langasek,

The incremental assembly is only triggered on [format]_raid_members.

SUBSYSTEM!="block", GOTO="md_end"
KERNEL!="md*", GOTO="md_end"

So something needs to be a block device and match a name md*. The current $ man 4 md , reserves:
       /dev/mdn
       /dev/md/n
       /dev/md/name
Or I would hope linux developers assume that /dev/md* is reserved for mdadm. So theoretically there is a possibility to *mis*assembly since there is no centralised linux kernel device namespace (that I know of). In practice such non-mdadm md* block devices are not known to exist yet.