I bought myself a ventura rack with a bag. Like it so far but I'm a bit concerned by how easy it is to remove the bag(or even disconnect the rack itself, leaving only L-brackets) with no tools or anything. So I wonder if any of you guys can suggest some sort of anti-theft contraption I can use to make sure the bag(and the rack itself) is securely attached to the bike and are not that easy to remove. For the bag itself, I think I can use a small d-lock or a lockable spring hook of sorts to lock it onto the rack but I'm not sure how to prevent the rack from being taken off the L-brackets. Any suggestions are welcome.