The design is based on a theme they had running already, with their previous effort being “You know it’s a MYTH” on a blue background.
Personally, I don’t see much problem with it. Sure, it’s going to come across as arrogant and intentionally inflaming, but then what billboard put up by atheists hasn’t been seen that way anyway? Here are examples of “offensive” billboards put up last year:
“You know its a MYTH”
“Millions of Americans are Good without God”
“Be Good for Goodness’ Sake”
“Don’t believe in God? You’re not Alone”
All of these are non-confrontational. Polite, even. And yet Christians see them as offensive, as a threat, and will complain about them, vandalise them, complain about our “tone”, and want us to just shut up, regardless of how polite our message is.
Well, it seems the AA have finally had enough of the Christian tone-trolling are are ready to do something actually controversial.
As to whether it’s a scam, your first point about how it started is beside the point, it’s what it is now that matters. And for 2., it doesn’t matter whether they’re scamming you out of money or your self-esteem, it’s still something taken via dishonest manipulation. I think “scam” describes the actions of the church hierarchy just fine.