Bad deal. I havent had a bag stolen yet but, I took a proactive approach. I bought 1/8" steel cable and crimps at the hardware store. Ran the cable through a nylon loop at the back of the bag and crimped it back on itself. made a loop in the other end and ran it under the seat to a seat post that the front seat snaps down on.
May not keep it from getting stolen but, thieves are gonna have to work at it. I also don't keep anything of much value in it.