I've been through 10 of them this year alone! They either forget to put them back on or are taken somewhere along the line by baggage handlers looking for valuables. I've gone back to using cable ties pulled all the way down. If you fly from an airport like BNA, Southwest has a TSA checkpoint there that, in most cases, opens and checks every bag before it goes down the conveyor belt. In that case, I simply put the unfastened tie through the lock holes and they are very good about replacing it and pulling it all the way down before sending it on. Much improved system with less theft than we used to experience there.