Clickbait title. There was a story recently that said that <i>all</i> of the devices had flaws with MAC address randomization. There's literally nothing special about the iPhone here.
This is known behavior: according to the iOS 10 Security white paper [1], "iOS uses randomized Media Access Control (MAC) address when conducting Wi-Fi scans while it isn't associated with a Wi-Fi network... Note that Wi-Fi scans which happen while trying to connect to a preferred Wi-Fi Network aren't randomized".<p>I haven't put much thought into it, but I wonder why they don't randomize all probe requests...<p>[1]: <a href="https://www.apple.com/business/docs/iOS_Security_Guide.pdf" rel="nofollow">https://www.apple.com/business/docs/iOS_Security_Guide.pdf</a>
Of course the neighbours could always find this out anyway by watching the traffic on your channel as there is never any MAC randomisation involved in talking to a known access point.