During my time there, the company would never actually do something that was technically wrong (or lying), with a couple of exceptions where some individual went too far and wasn't caught in any review. There were certainly UI elements that were misleading or suggesting (never claiming) of something being a freebie when it was included in the chosen rate. These sort of changes consistently received internal criticism, but ultimately due to the outstanding A/B testing tooling, were shown to be worth too much money for the detractors to succeed. There were maybe a handful that were rolled back due to internal criticism.
In any case, it seems unlikely that booking would implement the change you describe.
NB: the actual availability was always controlled by the hotels, as were the prices - booking does not own inventory, unlike some of its competitors!
Edit: removed surplus punctuation.