Padlock to secure cargo bike bag

My New Cycle Truck cargo bike has a giant pizza delivery bag modified to sit on the front rack. This bag is very well suited to this purpose, and it was quite inexpensive, but I put some work into it so that it would strap securely onto the rack, and I would hate to see it stolen. I also don't want to have to remove it all the time - it's nice to be able to ride to a grocery store and leave the bag on the bike.

So to deter theft, I installed two grommets in the bag, and got a combination padlock with a fairly long shackle. To steal the bag now, A thief would have to cut out the grommets, destroy the padlock, or remove the rack. But I can still remove the bag pretty quickly.