Apparently my logic was faulty in Babies-R-Us earlier when I decided to buy two boxes of the next size up diaper for Little Spaghetti to take advantage of their great sale. My logic: diapers can't really be too big, can they? I mean, can't you just put them on a little tighter, and they'll work all the same.
Learn from my fail: yes, diapers can be too big. They may catch the pee alright, but only because they go up to your kid's armpits when you put them on.
The upside: at least I bought diapers that are too big instead of too small. I just have to store them until he grows into them.