Providing benefits to users who click an ad?

Hello,

I'm currently using AdMob for ads, and I'm wondering whether it's against the AdMob TOS to give a user benefits when an ad is tapped.. I gave the TOS a cursory look-over and it says..

"If User is a publisher, User shall not, and shall not authorize or encourage any third party to generate fraudulent impressions of or fraudulent clicks on any advertisement,..." in the "Restrictions" section.

For example, in my case, I have a $0.99 in-app purchase that unlocks some functionality, but I'm looking into making a system where, if the user taps the ad banner n times, the functionality is unlocked for free.. This would probably fall under the "authorize or encourage any third party to generate fraudulent impressions.." category, but if the functionality is unannounced and hidden (until the user taps the ad n times), this would neither be authorizing nor encouraging fraudulent impressions... Right?

I remember there have been some games that give you extra points if you click on an ad... I was surprised when I saw these because they seem like they are in a clear violation of the TOS, so I'm not sure about my situation..

Anyways, thank you very much!