In response to a question about leaving panniers and other accessories on a locked bike, I don't.

If I am grocery shopping, I carry the panns with me and use them as grocery bags. The grocery stores I shop in encourage customers to bring their own bags, so voila. The lights, computer and other easily removables go into the back pocket of my cycling jersey. If I am at work, the easily removables go in the panns and the panns sit under my desk along with my cycling clothes which I change back into after work in the bathroom. If I am camping the panns go into the tent. I only carry at the most 2 panns for commuting.

I don't use the front 3rd and 4th bags unless I'm doing extended cross country travelling, which will hopefully happen at the end of September, Austin, TX to Little Rock, Ar.