How would you test whether the big red button with the locked cover still works though? I mean that's the kinda thing you don't want to see broken (mechanical failure, rust, etc), and these systems can remain unchanged for decades. You have to be able to test the real thing somehow, which gives a chance for accidental triggering.
> How would you test whether the big red button with the locked cover still works though?
Simple: you don't put the button behind the cover, you put the media with the scary message behind it. Then you can test the whole transmission system with less chance for mistakes.
Ironically, this was exactly the solution to the last big EBS failure, the "code word hatefullness" incident in 1971. Back then an operator had to load a tape into the transmitter, but one day he loaded the wrong one because the real and test tapes were stored next to each other. After the incident, they moved the tape to a different location:
> …In the past three tapes, one for the test and two for actual emergencies, were hanging on three labeled hooks above the transmitter… In the future only the test tape will be left near the transmitter. The two emergency tapes [will be] be sealed in clearly marked envelopes and placed inside a nearby cabinet.
