Why would Google do such a con? This technology is clearly plausible so it doesn't really make sense. I assume it was just fear of demo gremlins that made them

Why would Google do such a con? This technology is clearly plausible so it doesn't really make sense. I assume it was just fear of demo gremlins that made them use a recording. Also, you could argue it is unethical to broadcast a phonecall with someone live, and ruins the fun if you get permission in advance. I assume they did it, then got permission afterwards, and Google being Google, it didn't occur to them that people might want to talk to the callee.