Very easily done at 0140 in the morning after little or no sleep
It sure is.
I have done it twice, once where I used the ZFW instead of the TOW. The Capt was doing the walk around and I realised my mistake before he came back and corrected it. Told him about it in the cruise in the interests of learning/safety etc.
Second time used wrong runway , Capt was sitting beside me and picked it up when his data was different from mine.
I consider myself to be vigilent, I aim to be, but 8 hours into an 11 hour shift for the third day in a row on the back of the clock I make mistakes.
Fatigue is our industries biggest challenge in my opinion.
Framer