Just my two cents after reading all of the interesting posts last night and today about where Allison may have been left...
I had to drive over the bridge twice today (the flowers and cross looked beautiful
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
) and as I was driving I felt quite strongly that this murderer would not have stopped at or near the bridge. If the alleged murderer was anyone else then yes, I believe they may stop at or near the bridge in a panic. However, GBC and NBC would know this area very well, much better than the average person.
If you were aware of a better and more secluded spot nearby (eg up Wirraburra Rd) where you could park the car off the main road, you would take that option, right?
These people would know that area like the back of their hand I'm sure - through real estate and scouting. I also now believe that this is why they chose that area - familiarity. It seems too obvious and a silly choice on their part, but perhaps in their arrogance they didn't think she would be found for a looooong time - this is what I'm leaning towards. IMO