Earlier quoted context omitted.
And Booking pushing advertisements for the exact same hotel I've just checked on their service. I can't understand how that would seem like a good idea to anyone. This happened to me just last week. Unfortunately, it's the least of Booking's user-hostile traits. Like sending me e-mails pestering me to review a hotel I checked into less than an hour before. Or flashing "Hurry! Only 1 room left!" when I know for a fact…
All those little tricks you described are part of a strategy usually called Conversion Rate Optimization. They do this because it works. What you described was likely A/B tested. Some visitors to the site saw the nagging message, while others didn't.
Who cares if you need to lie a little bit, right?