No amount of training can prevent something like this. It's like today's browsers where the tab can be closed with ctrl+w and the whole window with ctrl+q. It doesn't matter how many times you've done it and how used are you to the position of the 'w'. One day you will close the whole window by accident.
Root cause analysis + countermeasure might have boiled down to "operator error due to shitty interface" + "we will tape a guard over F7 key, since it will never ever get fixed in software"
That's a dangerous way of thinking. 9/11 was big enough that it required a response. Not sure if we'll ever reverse the airport security stupidity that was such a response.
OMG I've never done that but now that I know about it I'm very afraid. If I do it tomorrow I'm blaming you.
Now, if you accidentally press Cmd + Q, it should prompt a "Hold Cmd + Q to Quit" instead of actually quitting.
Also, I made a mistake, it doesn't close the window. It closes all windows at once. Be afraid!
