Good News Clubs are more invasive than that. Those clubs are not started by each community as a whole, but by a radical Christian subset of the community. They are encouraged and supported by a national organization, which gives the clubs legal support when anyone complains.
The organization seeks to rip apart secular school communities or convert all children, specifically ages 4-14 because they know children of those ages are least able to reason about what they're told (they would phrase it: "most easily saved"). They are prohibited from trying to brainwash kids during school, but the distinction between normal school clubs and Good News Clubs is essentially non-existent. They try to blur the lines between school and Good News Clubs, in some cases setting up for the club during classes, so that students associate the adults running the clubs with school. They use food, candy, games, and other fun activities to lure kids in. Kids who get indoctrinated end up pressuring other kids, outside of and even during school. This is acknowledged by the organizers of these clubs, and they're thrilled. Paraphrasing, "we can't reach kids who don't join the club, but we can't stop kids from reaching other kids."
http://www.youtube.com/watch?v=04gTo31uLiw (Interview with the author of a book about these clubs)
http://www.goodreads.com/book/show/13132235-the-good-news-cl...