Idiots. Surprisingly, the world is full of them. Almost every time I go into my Gamestop I see somebody trading in a stack of games just to get one or two new ones, and it rarely covers the full cost.
I rarely go to these places to buy games, but I actually trade shit in somewhat often when I do. A game I'm never going to play again is worth absolutely nothing to me. In fact, I'd say owning it not only doesn't provide any utility, but there is a disutility involved simply because they take up space and clutter shit up.
For instance, I went into EB the other day to pick up Orange Box. I didn't actually know if they still took used games when I went in there but I traded in like four of them. I believe they were: FF12, Sly Cooper 3, and two of the Xenosaga games. I believe for those four games I got just over $30 or something like that. It might seem low, but it's $30 more then when I'd otherwise inevitability throw them out in the trash or give them away for free.
The other option is Craigslist or ebay. I checked the going prices of the Xenogears games on ebay first, and they weren't all that much more then I traded them in for. I mean, sure it'd be great to get an extra 4-6 dollars for each, but that's 4-6 dollars each to put up a fucking auction, monitor it, figure out my paypal info, transfer money into my account (minus whatever fees), go to the post office and ship all them out.
So, no I'd argue that I'm not an idiot at all for taking something with absolutely no value to me and initiating a transaction which then gives said items transferable value.