The guy from the first video was on our server a while, he became a sorta regular. I watched him almost constantly, he seemed suspicious the first day, but never did anything. Why do you think he did that? Also the video above this made me laugh. He was so relaxed, and he probably freaked out right after they said that. He bought the game too.
I don't understand when people say sprites are hard to make. It's quite easy to convert an image to a sprite, and even easier to use a pre-made sprite. Perhaps the hardest part is matching minecraft blocks to the colours, but constructing it is easy.
But it takes a long time. It is the same with any structure. Who wants to find their pink house griefed? Who wants to find their Golden Temple in tatters? No one. So the same goes for sprite art.