A tale a former engineering student at KU-Lawrence university told me years ago. There was a team of senior students working on an optical project for a professor. It was complicated, with sections spread out across the lab space. All was going well, but then they noticed measurements were changing between morning and afternoon. They would re-calibrate everything and all would be well.

Then one day a student noticed the equipment settings were changing while they were gone for lunch. Someone was messing with things while the lab was empty. So signs went up to warn visitors not to touch anything. It helped for a few days, but then it started again. Finally one student had an idea. He went off to do do a quick and dirty build, resulting in a box with a big red button on it and a fogged plexiglass window. Above this was black text displaying:

'DO NOT PRESS BUTTON'.

The box was left next to some of the more interesting looking gear. The others in the group blinked and asked 'What does it do? Sound an alarm? Or fire off a smoke bomb?'. 'No, just wait'

So they went to lunch again. Upon coming back they found the culprit, a sophomore from another part of the building. He was standing near the gear, shaking, one finger pressing the button. He called out, "What do I do?' and pointed with the other to the now red lit window that said:

'RELEASE BUTTON TO DETONATE'