I don't think you have a reasonable expectation of privacy when someone is speaking into a recording device, after intentionally saying a word to start recording.
Amazon may have some legal responsibilities to avoid the first scenario, but certainly not the second. The legal onus falls upon the resident to inform their guests of any recording devices. Nowhere that I can think of is it illegal to run a recording device in your own residence, or even to do so against the wishes of guests. It is only illegal (in some places) if done secretly. Amazon is well within reason to operate on the assumption that their customers are using their product only in legal ways.
