I had this happen recently at the Marriott Village in Orlando. They were funneling everyone who booked at any of the four hotels in the complex to the Courtyard...It was not a huge deal, but I still found it somewhat unethical that they were continuing to accept reservations for hotels that they knew to be closed. They did however send an email explaining the process and gave me points when I expressed concern about losing the specific room that I had booked with a kitchenette.
To me, the situation noted by the OP violates the spirit of the no-walking guarantee, if probably not the letter. I would be annoyed, too.