Luggage locks are a deterrent with a master key

A padlock on a case suggests security. What it actually provides is friction, and understanding the limits of that friction leads to packing differently rather than locking harder.

Screening authorities need access

Hold baggage is screened, and a bag flagged by the scanner has to be opened. If it cannot be opened, it is either refused carriage or forced.

Approved lock standards resolve this by including a universal keyway that screening staff can open with a master key, leaving the lock and the bag intact.

The consequence is unavoidable: a lock designed to be openable by a category of people is not a lock in the sense a homeowner would understand.

The zip is weaker than the lock

Most soft cases close with a coil zip, which can be separated with a pointed object and then closed again by running the sliders along the teeth.

The lock is untouched by this, and the bag shows no obvious sign of entry, which is why a locked case is not evidence that nothing was removed.

Hard cases with a latching mechanism resist this specific attack, which is one of the few genuine security differences between shell types.

The realistic threat is opportunistic

Bags pass through many hands in a short time, mostly in view of colleagues and cameras. The realistic risk is a quick reach into an unsecured bag, not a planned entry.

Against that, any lock works, because opportunism depends on speed. The lock does not need to be strong; it needs to make the bag a worse target than the one beside it.

A zip tie achieves much the same result, with the added property that it cannot be resecured, so a bag that arrives with it cut has announced that it was opened.

What should not be in the bag at all

Airline conditions of carriage typically exclude liability for cash, jewellery, electronics and documents carried in the hold, whether or not the bag was locked.

That exclusion is the operative fact. Anything valuable enough to want a lock for is usually something the carrier has already declined to be responsible for.

Cable locks and where they help

A small cable lock securing a bag to a fixed object in a dormitory, a train luggage rack or a left luggage room addresses a different risk: removal of the whole bag.

That is the risk a padlock does nothing about, and it is the more common loss on the ground, where a bag is unattended in a public space rather than inside a controlled system.