From the article:
The pilot had used the wrong Identify Friend or Foe (IFF) code, which allows ground radars to differentiate between friendly and enemy aircraft.
So let me get this straight: To avoid alerting ground radar of enemy aircraft all an enemy needs to do is set their IFF code to "Friendly"? I wonder what the conversation was like when the designed this...
Lazy Designer 1: "Just make it a switch, Friend or Foe"
Lazy Designer 2: "But it's that a little too easy to fool?"
Lazy Designer 1: "Nah...why would they lie?"

