A while back, I got one of those Visa gift cards. As soon as I saw it, I recognized what it was. I'm no stranger to those gift cards, because I've had to buy a couple of them as gifts for others in the past. The idea is that it works just like a credit card, so the receiver can spend it on pretty much anything he wants. And since the person receiving the gift card doesn't have to pay for the amount that was pre-loaded on to the card, it's essentially free money. As I'm discovering, though, there are a couple of minor details that can make using the gift card all sorts of interesting. For example, my friend was telling me that, on occasion, restaurants will keep the "account" open for a few days. I'm not entirely sure I understand the rationale, but apparently the tip is treated differently than the meal itself. It sounds like some sort of bookkeeping oddity, and normally I'd just laugh about it. However, this particular oddity can mean that th...