This would indeed be a problem at the start. But after some time it could weed out. People wanting to share illegal images would go away from the site if they ger rejected. We could expect a significant drop in nasty images.
You would to expect a significant drop in traffic after the ensuing PR nightmares, fbi raids. Followed by years of lawsuits from people who claim PTSD symptoms and what not after being forced to watch CP.
