I'm usually leery of words like "indoctrination," truth be told.  Hysteria isn't my style, or I try for it not to be, at any rate.  However, the tactics used by these groups lives up to the word, I think.  This video showed up a little while ago on the Richard Dawkins Youtube channel, and though it's long its content is both interesting and alarming (and, in anticipation of the usual criticism of any of the Big 4, not at all shrill, strident, or closeminded), and definitely worth watching.  

Now, the subtext in the video (though not explicitly stated) is that this sort of thing ought to be banned.  I would disagree, myself; I rather prefer the sort of impromptu tactic mentioned later in the video, wherein parents of different faiths (or lack thereof) send flyers, reading material, and promotional junk for their own beliefs in the same way that the Gideons send Bibles home with children.  After all, in the marketplace of ideas, the best will win, right?