Up to now we just delete it. We coded an admin for that. It takes time because we have to read the claim and assess the legitimity of it, not for the deletion.
Assessing said legitimity is tricky. Not because people lie, up to now they have been pretty decent, but because you really don't want to be tracked while following potentially child pron links, so it may take time.
Scaling moderation could become a problem if 0bin becomes more mainstream, but with so few reports, it's not a problem right now.