Personally, I couldn't travel without locking my belongings.

"Lock it and check it. This resettable three-dial combination lock features the Travel Sentry® mark, which enables TSA to easily unlock and relock your luggage for security checks. A red ring will appear around the base of the shackle if your luggage has been searched. Available in leopard, polka dot or zebra patterns." (via belle-hop.com)