I was thinking about placing this text next to a link unit. "These links will take you away from Example.com." or "Example.com not what you're looking for?" or "To exit Example.com:" This is because my site is highly scientific/technical about how widgets work, and the only ads which will ever be served are of the "Buy a cheaper widget", "Widgets in Yourtown", "Get a widget sooner" type. (There's no market in teaching technical widget information.) So the ads will only serve their purpose as an exit route for people who have arrived at my site but see immediately that it's definitely NOT what they are looking for. (Additionally, people learning about how this widget works won't want to buy one ($millions), use one (your hospital doctor uses it on you) or find one near them (you'd just go to your local hospital)). Is such text next to a link unit allowed? Is this attention "undue"?
Not allowed, what you can put is "Sponsorised links" or "Advertisement" bettter leave it without text and make it a natural thing to click on them by blending the adsense block with your website design.