The Whitecloak Rules
For aspiring young Children of the Light
If you don't like them, they must be Darkfriends.
If they don't like you, they must be Darkfriends.
If they're rude to you when you ride into their village, insult them, put them under guard, and hang half of them for no reason at all, they must be Darkfriends.
If they're polite to you, they're obviously trying to hide something, so they must be Darkfriends.
If someone gets sick and then gets better, there must be an Aes Sedai around, who by definition is a Darkfriend. The person who got better is probably a Darkfriend too. Hang them just to be safe.
If you manage to find the Aes Sedai, hang her, even if she's already dead.
If you hang people and then find out they were innocent, don't worry - they were probably Darkfriends anyway.
And the final rule, for Children who want to be absolutely sure:
Ask them. If they confess, well and good: if they deny it they must be Darkfriends. Why else would they try to hide it?