[djhworld]

I believe the terms and conditions for the Alexa SDK state you can't activate the Alexa Voice Service via voice, your user has to purposefully interact with something like a button to use it.

EDIT: I'm wondering if this is a legal thing, i.e. they don't want any tom, dick or harry creating "always listening" devices associated with their brand, or they just want to differentiate their Echo product and not have competitors