Steve, I'm an advocate of the old Banana In The Handlebar Bag school... I've long been a victim of the 2AM leg cramps as well. For all I know it's a placebo effect of just telling myself this will help, but stopping at the top of a decent hill three quarters through a ride and chomping down a banana seems to make a hell of a difference. They're cheap, too!
And no, I don't throw the skins on the ground, I keep a sandwich baggie in the bag as well and get rid of it when I get home. Ever ride a path after a big road bike event? Blackening banana skins all over the place.