Pick a hotel from a search first — every result card has a Is this discount real? link. Go to search.
A diagram of the method, not any hotel’s actual prices.
A discount is a claim about two prices: what you pay, and what you supposedly would have paid. We can only check the second one by watching it. So we ask the same hotel for six different arrival dates and see whether that “public price” moves at all.
A diagram of the method, not any hotel’s actual prices.