I work in TV. During my first job at a small market station 30 years ago, I was training to be a tape operator for a newscast. All the tapes for the show were in a giant stack. There were four playback VTRs. My job was to load each tape and cue it to a 1-second preroll. When a tape played and it was time to eject that tape, it was _very_ easy to lose your place and hit the eject button on the VTR that was currently being played on the air instead of the one that they just finished with. The fella who was training me did something very annoying, but it was effective: every time I went to hit the eject button, he would make a loud cautionary sound by sucking air through his closed teeth as if to tell me I was about to make a terrible mistake. I would hesitate, double check and triple check to make sure it was the right VTR, and then I would eject the tape. He made that sound every single time my finger went for the eject button. It really got on my nerves, but it was a very good way to condition me to be cautious. Our station had a policy: the first time you eject a tape on the air got you a day off without pay; the second time put you on probation; the third time was dismissal. I had several co-workers lose their jobs and wreck the newscast due to their chronic carelessness. Thanks to my annoying trainer, I learned to check, check again, and check again. I never ejected a tape on the air. It certainly would not have been a half-billion dollar mistake if I had, but at that point in my career it would have felt like it to me.