I ditch the back seats and passenger seat when I go out to play.. shaves about 100lbs. The jack and spare have been out of the car since day 1. I left them at the dealership. If I get a flat on these 18's it's "Hello... OnStar Roadside Assistance?"
I don't know if anyone has read/watched Generation Kill, but the Marines had the reporter buy them, among other things, Adult diapers. Later, they say that there are some situations where they just can't leave the vehicle. Hence, the need for a wearable toilet.