Sleeping in a hotel can be uncomfortable for trivial reasons, but feeling unsafe shouldn’t be part of the experience, which is why a simple trick, with a glass next to the door, is circulating as an improvised “alarm” to avoid silent entrances at night.
According to the British portal Express, the idea was shared by Nina Bolders, flight attendant and author of the “Fly Me to the Vegan Buffet” project, who says she uses a homemade system with cups/mugs so that any attempt to open the door causes noise and wakes her up.
The method gained strength because it is immediate and does not require purchases: just use what already exists in the room, such as a mug or a glass, to create a “sound signal” if the doorknob moves.
How the “cup trick” works and its limitations
In practice, the objective is not to “block” the door, but rather to create noise: when placing a glass on the handle/knob (or nearby), any movement tends to make the object fall and wake up the person who is sleeping.
This can give an extra feeling of control, but it is worth having a realistic expectation: it is a detector (warns), not a security system (prevents). Therefore, it does not replace the locks or resolve situations where the door no longer closes properly.
Another important note: if you use objects as a “barrier”, ensure that you do not create a dangerous obstacle in the event of an emergency (for example, having to leave quickly due to a fire). The rule is: reinforce security without compromising evacuation.
What is recommended by security entities for hotel rooms
Security guides for travelers insist on the basics that almost always work: testing locks, keeping the door always locked, using secondary locks (chain/latch) when they exist and not opening to strangers without confirming with reception.
If you want a simple and effective solution, the most repeated recommendation is a door wedge, some hotels have them and there are portable versions. The International Federation of the Red Cross suggests this type of reinforcement, especially when sleeping or in the shower.
Another point that is often ignored: check that the room has basic safety conditions (e.g. alarms, exit routes and, when applicable, a carbon monoxide detector).
If it gives you peace of mind, you can use the glass as an extra “alarm”, but combine it with measures with real impact: active locks, secondary locking, and confirmation of identity before opening the door (a quick call to reception solves many situations).
According to , and for valuable objects, the rule is to avoid leaving them visible and, when available, use a safe (in the room or at reception), always keeping essential documentation with you.
In the end, the virality of the “cup trick” says more about a common need, to feel safe in a new place, than about an “infallible technique”. And that can be positive, as long as the main solution remains the simplest: door tightly closed, locks used and checking before opening.
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