I believe the alerts false, statistically speaking, these alerts don't make sense. Every room you click is in an end-of-world situation where you have to book now otherwise "who knows" and 5 days later the same amount of rooms is available and the same exact scenario is presented for all rooms/hotels.

ps. What I usually do, is look at booking.com for hotels at cheaper prices and then head to the hotel's website. They usually have more categories of available rooms and at a cheaper price.