Some good CPM based advertisers pay 10 dollars for 5000 impressions, so you would be getting 100% profit on this huh? Say Tribal fusion? This would be good for an established site with about 10000 hits already.
I can confirm that this *could* put you in hot water. Some time early this year I ran a promotion on a website in which users that attracted 5 qualified new users of a free service got some products for free as a reward. 5 qualified users was quite a task to achieve for this niche, even for a free product. I didn't think that somebody would practically pay for traffic to get the rewards I was offering. I was informed that pay-to-surf, auto-surf, pay-to-read, and pay-to-click traffic was considered to generate invalid clicks and impressions and that my expereince with adsense may be coming to an end. Examining analytics and weblogs did resolve that the traffic came from a source that sells x visitors for y dollars. Be very wary, The traffic I got was targeted for sure, the person that paid for the traffic reached the 5 mark in a few days, and the 5 people that were counted actually signed up and registered a unique hardware product that is not universally common. Being targeted does not make it okay!