Most likely the ductail is there to stop the passenger sliding off the back...ever been a passenger on a bike that is accelerating fast? Easy enough to be caught out by a sudden burst of speed at take off. That and the comfort feeling for the passenger of not feeling like he/she is about to slide off.
Yeah. I'd say I'd ask Corbin what they think about using the passenger area of a gunfighter (solo) seat as a place to really sit. I wonder if the foam is up to it, other than short rides, and if they even recomend it. Its going to have a slight tilt down to the rear, or at least level, either of which would be death to an unprepared passenger.
That's what the "Gunfighter and Lady" is for. It has a pocket and a rear flip to "register" the passenger.
My HawkGT has the G & L. It was a real sacrifice to the looks dept, the solo seat looks so much cleaner, but I'd never put a passenger on the solo seat, and at times I'm called on to ride 2 up. On the K not so much as it had a big seat to begin with. Still, the G&L has a nice pocket for the driver, the same Cafe style buttstop and is lower than stock. While riding you never see the "Lady" part, and feel good in the gunfighter part.
The G&L also has the provision for a backrest which doubles as a sissy bar for luggage.