We were standing in line in front of the Amtrak counter at New York's Penn Station, looking to catch an early train back to Boston. Few people in the line had noticed the child-sized black backpack parked in front of the counter until several police officers burst onto the scene with dogs—presumably, the kind trained to sniff out bombs.

No one fled the line. Though images of the Madrid rail station bombings were fresh in our minds, most of us assumed from the start that it was just a child's pack, dropped while a parent fumbled with a wallet and train tickets, and then forgotten. That turned out to be the case. The whole incident was over in a matter of minutes, leaving us reassured that the authorities were alert and at the ready.

As someone who travels frequently on business, I confess to occasional impatience with security precautions, particularly at the nation's airports. But what I, as a passenger, go through—emptying my pockets, removing my shoes—is nothing compared with what the freight community faces. Terrorists' attacks on transportation systems have prompted the government to train its searchlights on the people who move goods by air, land, rail and sea. "You're the target," Admiral James Loy, deputy secretary in the Department of Homeland Security, warned attendees at a transportation policy forum sponsored by the National Industrial Transportation League in March.

And so, the government has stepped up container inspections and tightened up its rules on paperwork. Shippers who once dropped containers off at a dock with a promise to fill out the documents later must now heed strict electronic advance notification requirements or risk having their freight left behind.More rules are sure to follow.

Not everybody's happy about that. Inevitably, inspections create delays and pile up costs. But no one disputes the need for intense attention to security. Not long ago, a DC manager's biggest security concern was guarding against theft. Sadly, that manager no longer just has to worry about what might be taken out of a container; he or she now has to worry about what might be slipped inside it as well. In a world where even a child's forgotten backpack triggers alarms, it's hard to ignore Loy's call for vigilance.