[Yetanfou]

   I unplug it when I don't want to listen to music or put together a shopping list.

...which is when the device stores everything it hears, ready to send it to the mothership as soon as connectivity is reacquired.

No idea whether it already does this but a small battery and a bit of flash go a long way when it comes to overhearing that which was not meant to be overheard...