[woobar]

I think both of them don't need to send any data to the mothership and can process this phrase on device.

For instance, in airplane mode with no network access iPhone response to 'Hey Siri' is 'Siri is not available. Connect to internet'

[jonknee]

It would be shocking if Echo doesn't work the same way, that would be an incredible waste of bandwidth and AWS CPU power otherwise.