Affirmative.....75/76 FO

I'm just trying to understand someone's motivation for taking this guy up on his offer.....if I had 3 days off and felt the need to fly I could pick up a 3 day trip and be compensated handsomely....why would I instead decide to commit to probably 12 hrs. In the box and some additional briefing time (undoubtedly at some unGodly hour at night or early morning) with some total stranger met off the internet? Honest Question.