It is no longer Unfair! So here is the "backstory".
Inspired by a POST at AUGI, once upon a time Line Based families were not "Room Aware". This means that one of these families will not know what room they are in when you create a schedule for them and also include Room Parameters.
Back then the following was suggested by Autodesk Support:
A possible workaround is to add the room name manually in the Comments field of the family and then schedule that field as well.
If you read the post note that the original post (at AUGI) is dated 2006-09-15, almost two years ago. The original poster followed up today that the issue still exists but that he was able to nest his line based family in a regular family type to allow it to become "Room Aware".
However when I created a new line based family using a 2009 family template and tested it I found that it does work, the family is "Room Aware" now. Regarding the issue at AUGI I suspect that the upgraded family does not become "Room Aware" and it may be necessary to remake the family instead to acquire this behavior. Alternatively the light fixture may be above the upper limit of the room so Revit can't "find" it.