A lightning bolt of fear shoots down your spine when, returning late to your hotel room, you see the door is not fully closed. You know you closed it—and checked it.

Pushing the door a little you see that, not only is the door open a crack, but its bolt is thrown so that it can’t close.

This is what happened to my sisters at the Hotel Mercure in a Stockholm suburb. Luckily, it wasn’t the same day that they accidentally left their smartphone on the bed. (The phone was still there when they returned late that day.)

After the physical attributes of a hotel room, housekeeping holds our security in its hands. We can perform our hotel room security check and follow good security practices, but the maids can make our efforts moot.

A traditional hotel security threat has come from social-engineering burglars who enter rooms while maids are cleaning them and pretend to be the room’s occupant. To behave appropriately in these confrontations, hotel housekeeping staff must rely on their training, perhaps balanced by their own judgment and discretion. And anyway, rules are one thing; compliance is another.

Human error is a separate factor. How many times has that housekeeper finished a room, unbolted the door, closed up, and ticked it off her clipboard? Or, oops! Out of shampoo—she’ll just fetch it in a moment…

Mercure hotel management did not seem overly concerned by the security lapse. In compensation, my sisters were offered “a small dessert” at the lobby restaurant. The attitude, apparently, was that if they weren’t claiming a loss of property, well, no harm done!

I usually forsake maid service, leaving the “do not disturb” sign on the door. If you like your room tidied up (and even if you don’t), this is yet another argument for locking up your valuables, either in the safe or in your largest luggage.