We had the same situation last September.
My husband was dropping me and our luggage off at the dock and was going to drive the rental car back and then grab a taxi to return to the ship. When the guys taking our luggage in (they were port staff, not cruiseline staff) realized what he was going to do, one of them jumped in his truck and followed him to the rental agency and brought him back. We couldn't believe it. Needless to say, both he, and the guys who took our luggage, got big tips. I have never seen such friendly, accommodating people in my life. Don't know if this is common practice or we just got lucky.