If it was one of the automated tray machines yes, they are designed for two people to load side-by-side, and I have often been directed to do so by the security person standing opposite. However, it can lead to considerable confusion about the order of the trays going onto the conveyor, as most people (understandably) want their stuff to go through (and hence come out the other end) together.

It's still a barking arrangement if you ask me. I used to prefer being sent through to the additional machines at Security South as they are of the old school variety and (I think) process pax more quickly.