Advanced Match History Gold Bug

I just played the above game against a premade 5. While I did kick their butts, I will admit they were just messing around, so not too much pride there. But if you go into the stats, and check nunu's and shaco's gold earned vs their gold spent, you'll noticed that they both spent about 2k more than they earned. Just thought you might find this funny/interesting/horrifically gamebreaking.