I am not condoning the storage of Alexa recordings, but it should not be a surprise to anyone. I setup an Echo for my elderly mother precisely for the reasons someone previously mentioned for use with a disabled person. In doing so, I installed the Echo app on her iPad so that we could setup certain services. While looking around the app I found that it can provide your complete history of Alexa use including being able to playback the audio recordings it made when you had made a request.
If you do own an Echo device, checkout the app. It's kind of creepy.