Has Artificial Intelligence gone too far?

Artificial intelligence has a new challenge: Whether and how to alert people who may not know they're talking to a robot. This week, Google showed off a computer assistant that makes convincingly human-sounding phone calls, at least in its prerecorded demonstration. But the real people in those calls didn't seem to be aware they were talking to a machine. That could present thorny issues for the future use of AI. Among them: Is it fair -- or even legal -- to trick people into talking to an AI system that effectively records all of its conversations?