With all the Google I/O stuff coming out, how can I verify that I have an actual human on the phone using only voice? Are there still vocal things humans can, but robots can't do?
Conditions: the person on the phone is a stranger (so personal questions won't work), and the verification must be voice only.
(Also, I understand Google Duplex may be just an overhyped demo that will turn out to flop like the Pixel Buds. But eventually such a bot would be created, right? If so, what's the best verification?)