Pedo Baiting is what bored trolls do in their spare time for lulz. They lurk in forums, waiting for their victims. The troll pretends to be a young, naive minor, and simply waits for the pedos to turn up. They then start a chat, flirting until they get the contact information and name. Then, they post another message pretending to be the FBI, CEOP, police or some other authority figure. They continue doing this, working the victim up into a panicky frenzy, then sit back and cackle in delight at the misery they have caused.
Troll: So can I have your number?
Foolish Pedo: Sure Baby, it's 0191 5674834, you gonna send me some pictures?
Troll: The Child Exploitation and Online Protection Centre (CEOP) has logged the IP address....
Doomed pedo: OH GOD NO.
Troll: Haha, I love pedo baiting!