Thanks for the great advice! I was hoping to hear that the stoker doesn't usually have to unclip. This could actually be a nice way for my husband to practice using clipless in the real world. I was also thinking that the stoker might have it a little easier in terms of being able to stretch and look around... not that we're doing any epic journeys, but I imagine his neck, hands, and shoulders are just as unaccustomed to bikes as his legs.
"And people who know about the stronger of two similar sized riders taking the back will just assume he's stronger" I'll let him know that! He doesn't have any ego issues about letting me drive, though, and I'm sure he'll just say he prefers the view if anyone asks!