I recently noticed that google are trying to promote its mobile business with its mail ect very often. Google never buy ads and want spread its product through its network to generate more profit with lowest pay clicks. Just block this kind of ads and you will be fine. Correct me if I am worry.
I actually notice the mini.google.com ads on my site and blocked them since 3 days ago. You know, after i blocked them everything is going wrong with my stats, CPC dropped by 50% (and even more for some clicks). And i hate how the panel doesn't display stats properly, i see some clicks on channels while impressions are 0 and earnings like 1 cent wtf...