why to waste time behind the things which are not permanent, i am not sure when you will be banned doing so, google is very very strong than you may every think. see if you can fool the google so easily then what the expert hackers, black seo gurus can do with them ???? Dont even try it.....
I am not sure how, but i am damn sure they can catch it. Believe me, i have tried lot much tacnics just like this. they can use many parameters like time between page load and ad clicked, how long they remain on ad target page, how frequent your friends clicks your ads, how natural your site gets visitors and clicks, what is your ctr, etc, etc, and lot much.. this is just out of your (and mine also) imagination, because it's all about money, if google is not deadly secured, you can simply understand that how much revenue loss they have to face every minute and every seconds just because the guys like yours ????
You will be banned asap. Google is fast than you think. It does not matter if you have told someone to click your ads or not, even if some random people click more ads, you'll be kicked off