In the order moved with the first identified item being the last one moved.
Maybe lol...
I'm pretty sure I played with this for like 10 minutes before. If you have 20 bandages in your pack unstacked, and move them one at a time into a container, then do a find for bandage, they will show up with the last one moved being the first one found.
I got bored with it and never revisited it, until this very post 
You are right!
I had these tests some years ago,too and it seems like the order comes up as the Datastream goes to client.
Example:
ID 1 -10 are in Bag a
now you Scan Bag a and getting an Index with an Order 1-10
then you move 2,3,7,5,4,1,6,8,9,10 in this queue to Bag b
doing Scanitems will give you exactly this Order!