Has this not been shown to happen?
Has this not been shown to happen?
1. While in Japan, or during the planning of the trip to Japan, the persons visited websites that indicated a preference towards visiting Japan, and sometime later an ad network connected the cookie with their past behavior and served an ad for a flight, or
2. Someone has created a hitherto unknown stealth malware designed to circumvent the "microphone on" notification on smartphones and exfiltrate audio from a user's device, deployed the infrastructure to store and process the audio, and then done everything already needed in scenario 1 to serve ads for a flight.
Any moderately-skilled network engineer or security professional would be able to instantly tell if a device was sending audio to a remote server if told to look. And highly-skilled people are actually looking.