Apple has invented a Privacy Security Feature for Siri that will detect an Imposter's voice & not execute commands
Yesterday the US Patent & Trademark Office published a patent application from Apple that relates to Siri not executing a command if the voice making the command isn't the owner of the device. Siri's 'Magical Experience" will extend to privacy and security in future versions of AirPods through to Macs.
As part of Apple's privacy strategy, the company is developing a voice recognition system for Siri so that it will only execute a command if it recognizes the device owner's voice.