the thing about pedo rings is that they are ultrasecretive, so there's no way of really knowing much about their activities, unless you are NSA/CIA who are spying on them.
Many politicians and powerful men are pedos, so I certainly believe that being an average joe you could encounter or expose one by posing as a little girl for example rather easily. It's a whole grey area of shitstorm but I think it's either the following or the combination of the following:
A) The police is bought by powerful pedos.
B) Powerful pedos are wealthy thus they are never stopped/harassed by the police an never exposed.
C) The police is horribly bad at catching pedos, probably just as bad as in their war against drugs.
In any case pedos are pedos, they tend to have lower IQs, think with their cocks and generally not too hard to fool.