I know, the [RAF] tag doesn't give the best impression, but bear with me. Just posting this to try to contribute, and I tried searching but couldn't find anything about it, but if it's a repost, pew pew shoot me down and then lets talk about bunnies instead.
Edit: Forgot to add, the topic is a bit misleading, but I couldn't really phrase it right.
Now, this is not in any way a fool proof scam, and it requires you to find a really gullible person and exploit the situation.
Story time:
So, I was starting up a new alt, and since my friend (who I recruited earlier and leveled with) had leveled up two chars, I could grant my alt alot of levels. So there I was, in STV (Don't ask me why, no particular reason), dinging like crazy, and around 35-40 somewhere a hunter gets curious. He doesn't know about RAF and thinks I'm exploiting something.
Now, you probably know where I'm getting at here. It's one of those situations that you just love to take advantage of. So this is not really a scam that you're looking to find, but anyhow.
He of course asks me to share the secret, and after some conversation he agrees to pay 1k gold for it. (In the end I regret not setting the price higher, an epic flyer for my alt would be nice.)
So all in all, I got paid for telling someone about Blizzards RAF. Depending on how you phrase yourselves, you could probably get a temp ban or such, but if you don't mention it as an exploit or other "illegal activities" I doubt Blizzard is gonna ban someone because another guy was too stupid to keep up to date with the news. (Feel free to correct me if I'm wrong)
Short version:
If you're granting an alt levels, don't do it in secret, do it in the open where there are lots of gullible people, you might end up richer.