Real scarcity is information: “the 7pm showing has 3 seats” helps you decide. Fake scarcity is a costume worn to stop you deciding at all. The countdown that resets on reload. The “only 2 left!” that is always 2 left. The “18 people are looking at this right now” with no way to be true or false.
The mechanism is deadline pressure aimed straight at your slower, more careful thinking — hurry, don’t weigh it, decide before the number hits zero. Nothing happens at zero. There was never a zero.
The tell is beautifully simple: reload the page. A real deadline keeps counting from where it was; a fake one starts fresh, because it was only ever counting your hesitation. The fix is to only show a timer when there’s a true deadline attached to it. Urgency you have to manufacture is urgency the product didn’t earn.