Wow! Common sense! thanks for that!A test is certainly wise and needed to work out the kinks. However, people generally have an expectation of privacy in a hotel room. Besides, people who use smart speakers also have smart phones which can fill in as the digital assistant when not in the home.
Making these opt-out is a bad idea, and I think Disney will figure that out. Can you imagine checking in and being told, "By the way, all rooms here have a smart speaker, if you want total privacy, you'd better unplug it." Making smart speakers available for people who request them is a much better plan, and should be Disney's goal.