I use twist ties from plastic bags. The wire is strong enough to keep my bags from opening. The TSA always has always put the twist tie back on after they inspect the inside of my bag. I think they work better than something they would have to cut off, like a cable tie or lock. I fly a lot (30+ flights per year), and the twist ties have never been removed from my bags. I'm sure no one would think I have valuables in them either since the bags are not locked. I've never had anything taken out of my bags.