Security researchers have long warned of the dangers of using master-keyed locks -- if thieves get their hands on just one key, they compromise all of the compatible locks at the same time. And unfortunately, the US' Transportation Security Administration is learning this lesson the hard way. It briefly let the Washington Post show a photo (we've blurred the details) of the master baggage keys it uses for approved locks, giving crooks a crude guide to making duplicates. And you can't just switch to a non-standard lock to get around this, since TSA agents will rip it off if they catch it during an inspection.