Here's a tip passed on to me by a luggage salesperson in downtown MIA shop, reportedly told to him by baggage handler friend who worked at MIA:

Don't use a padlock of any sort because the self-sealing zippers can be opened by poking them with a ball point pen and resealed by running the zipper back and forth -- you never realize your bag's been opened until you yourself open it!

To lock a bag, use a cable tie (aforementioned "zip tie"). To prevent the self-sealing problem, be sure to tie it through the padlock loops, and then through the handle before cinching it down. It then can't be opened and self-sealed to "close".

As for the opening . . . well, I think you can get by with nail clippers on most flights now.



------------------
It's not a perfect world.