When Charles sees Reverend Danforth "cure" the same group of people for a second time, he asks the guy standing next to him where he will be preaching next, and the guy knows the exact time and place for the following day. If the Reverend really was influencing people like that, you'd think that more people would be following him to his next worshipping service, and they would know then that he was lying. It appears that nobody except Charles and the Walnut Grove townspeople ever thought to go to another service. You'd think more people would be flocking after him, especially since Reverend Danforth obviously wasn't able to stay in all those towns he visited on a regular basis, and in reality, once they saw him "cure" someone once, hundreds of them would want to come back and ask him to perform miracles for them. It was pretty odd that Reverend Danforth clearly never stopped to think that maybe someone would see his little act twice in a row.