It looks brilliant at first glance. Wrap a little aluminum foil around your doorknob before going to bed, and according to countless social media posts, you’ve created a simple warning system against unwanted visitors.

The idea sounds convincing enough to spread quickly. If someone touches or turns the knob, the foil may become wrinkled, torn, or displaced. In the morning, you supposedly have evidence that somebody tried your door while you were sleeping.

But there’s an important problem.

Aluminum foil does not prevent a door from opening. It doesn’t strengthen the lock, stop someone with a key, or provide the protection offered by proper security equipment. Even as an indicator, it can be unreliable because ordinary movement, pets, wind, or someone inside the home could disturb it.

The bigger concern is the false sense of security it can create.

Someone who believes the viral trick is protecting them might overlook measures that actually matter: locking doors and windows properly, repairing damaged locks, using appropriate outdoor lighting, or installing legitimate alarms and security cameras where suitable.

Foil still has plenty of useful purposes around the house.

Protecting your home shouldn’t be one of the things you depend on it to do.

Sometimes the most convincing internet “life hacks” aren’t dangerous because of what they do—they’re dangerous because they make us believe we’ve solved a problem when we haven’t.