Withdrawing after a Round One Upset Loss

As a player and TD, I've noticed an interesting phenomenon that's more common than people realize: players withdrawing from a tournament after suffering an upset loss in round 1.  (As a footnote, keep in mind per USCF rules, the tounament fee cannot be refunded once you've played a game).

A loss in chess is very tough on the ego for many.  There's a sports psychology term, "loss aversion," which I've previously mentioned.  The idea is that in any competitive endeavor, the pain of losing is a more intense feeling than the thrill of winning.  Some chess players are so crushed by a first round upset that they don't have the inner fortitude to continue and would rather drop out.  I get how tough some losses can be but that seems extreme.  

If you browse through crosstables of chess events both big and small, you'll see many withdrawals like this, perhaps after round 2 for some. As a TD, I've gotten withdrawal e-mails late in the evening after round 1 has ended or early the next morning, usually with no explanation or one that seems contrived.