Unnatural Attention for AdSense referrals?

[bostons4u]

I am not sure what they mean by you can't create unatural attention to click an add

Can I offer a free marketing ebook to them if they sign up for adsense under me?

[skweb]

How will you find out if somebody signs up? Google does not share that information with us. What you should not do is a quid pro quo. Offer your ebook to anyone who wants it for free. At the same time, you can suggest that visitors can sign up like you with AdSense to monetize their content. There you can provide the referral link.

[AdSenseAdvisor]

You can feel free to encourage users to sign up for AdSense using your referral buttons, but not to offer any rewards or compensation in exchange for doing so.

This would fall under the program policy that states that publishers "may not compensate users for viewing ads or performing searches, or promise compensation to a third party for such behavior."

Hope that clarifies,
-ASA