Answer by Dan Novi:
I was flying from an airport in New Zealand. Honestly, I can't recall which airport, but in this case, all passengers were required to go undergo full screening to get into the terminal (I specify this because from what I've seen, this is not always the case for domestic flights in NZ).
Just as I passed through security and collected my bag, I saw a security officer pick up a power cord with a worried look on his face. He walked briskly to his supervisor, who was right near me, and whispered something in his ear. The cord that the guard found was the power source for the metal detector and no one had any clue as to how long it had not been plugged into the wall outlet. Since it was not taped to the ground, it's likely that a security officer accidentally kicked it out of the outlet while walking by (that area was off-limits to passengers). But there was also a remote possibility that it was maliciously disconnected by someone.
The supervisor thought for a moment then called for everyone to leave the terminal to be re-screened. There were hundreds of people in the terminal and this seemed like an odd request, so many were reluctant to leave and pretended they didn't notice the request. Eventually, the command went out over the public address system and everyone was herded out of the terminal. Before anyone could be re-screened, bomb-sniffing dogs were brought in to scan the entire terminal. This took at least half an hour. And now the security line was massive since everyone was trying to get back in at the same time. It would be another hour before we would get back through the security gates. Several flights were delayed because most passengers were stuck in the security line, all because someone tripped over a power cord.