General etiquette is to drop/pick up whatever suits you, and not worry too much about the reserves. Reserve is reserve. I hate it when reserves whine that they had to drive in because somebody dropped the last turn (probably to catch a flight home in time to see their kids before bedtime). On average, most of us did our time in the hole before we got a line. It's asking too much to worry about a hypothetical reserve (who might want to go fly anyway) before you adjust your schedule.

But once on a trip, I would never screw over my crew by "volunteering" them to do something they didn't want to. But you can always have the discussion and reach a group consensus (I have).