At our library, in theory, when one ref librarian takes over the ref desk, the one who was there tries to fill in the successor with info on any patrons in the library doing major/tricky research at the moment.
This was the summary from my coworker when I took over the desk just now:
Uh...there's a guy doing research....for law review.
Me: What about?
Coworker: Well, not really for law review. A research thing. [he leaves]