A: Because it’s always a good idea to have a backup source of light when you go camping!
We’re joking of course, this was in fact a mistake. We try very hard to avoid printing errors like this, but even so, accidents sometimes happen without anyone catching on until it’s too late. The good news is, the card that we lost was yet another Goal, which is an error that has very little impact on gameplay. Heck, we ourselves played a game or two with the first production deck (always a fun ritual for us) and none of us even noticed the error.
In other words, it could have been a lot worse: if the card we’d lost had been a Keeper, for example, we would have needed to recall the entire print run. But this is simply a disappointment. You can decide to leave both copies of the Goal in the deck, or throw one away; either way, there are still 32 other ways to win.
Assuming the game sells well enough to warrant a reprint, we will fix the problem on the next printing, and when we do we’ll make extras of the “new” card for fans who want to update their decks. Until then, please forgive us for this mistake.