I'm too lazy to take all my stuff out, that's why I wanted a lock. Yeah you can most likely open it with a screwdriver, hammer, or perhaps even an impressive karate chop... but who want's to steal an innertube and lime green shell ?
The box is really not heavy, it's all the crap I tend to haul that puts the weight on. As a commuterI don't really care about weight that much. You haul it up the hill, it makes you go faster down the hill. End result...sexy biker legs.
I was lookin around at the motorcycle panniers.. waaay too big and heavy for a bicycle. I'll keep fishing around, something will bubble up.