He had inside knowledge. He put it out there that thousands might have discovered this to cover his source of inside knowledge.
Or he reverse engineered the locks for a project and learned this as part of that process.
Ever stop and wonder if your mobile phone might interfere with a car's electronics causing the breaks to lock at an inopportune moment? Can you guarantee with absolute certainty that this can't happen?
Yes, yes i can. All of my vehicles were built before the government mandated nanny system explosion, so my brakes are tied directly to driver input, not some resistor and relay switch.
You think all the switch ports are on? You think they will talk to just any mac address? You think the IDS will not notice your ARP poisoning?
Sure wired networks are a risk and there are ways around what I mentioned, but you are clearly talking about the follys of Windows Operators. Please do not call those folks System administrators.
Windows/AD based networks are just as legitimate as any other, the System administrators are just as legitimate as any other, and as soon as you put aside your arrogance, you'll realize that most businesses run windows on their office machines, and AD to manage logins. That said, my place of employment is an international corporation, so, we qualify as Real Enterprise, and the switches have no down-ports, so the 'walk in, plug in, profit' method would work just fine. i'm not in charge of the network, so it's not my problem, but i still recognize the potential flaws in the system.
When you go out to buy, don't show your silver.