Not an "accident." It was an "incident."
Yesterday I hauled a giant soft-sided cooler on top of the Snapdeck. My lovely wife serves food to some hungry people every other Wednesday night and she often has this type of thing to return to church the next day. Since I work there, it's easy for me to just throw it on the Xtracycle and bring it back when I'm headed to the office.
Well, this thing was easy to mount and carry (as most things are on the Xtracycle). But when I went to dismount, I swung my leg over the back of the bike while standing on the pedal with the other foot... all of this while still rolling, of course. When I went to fling my leg over the back my foot got caught in the straps of the cooler. I struggled for a few moments... then... went... down.
I bruised my hip and somehow removed some skin, but there was no real damage... other than looking like an idiot. This type of thing was bound to happen eventually. But I'll certainly dismount differently now that I've learned my lesson.
I'm still learning the nuances of carrying cargo on a bike. :)
Get out there.