<Someone halp! That Q guy iz steelin all muh listenurz!!!!!
Some knew when it was introduced (social media, letting children on social media), and later verified by Q. Many did not take the reality of what was shown to anons really to heart, or understood the gravity of it.
Scoping pretty teens travelling alone in airports is one thing, and has a random quality to it. Social media, with a 'special' level of access provided by @Jack & co, is an actual catalog of children that headhunters peruse to find children that match their client's preferences.