Do you really think google is going to put up their reputation for a couple bitcoins?
I've seen many cloud mining/ponzi sites being advertised on google, it's been a long time... will all this time google not know of the existence of ponzi sites?
OP doesnt have any idea about adwords and advertisement/banners etc. . Google doesnt have any relation with it since its just an advertisement and you can always report those banners or whatsoever since those are againsts on their terms but still useless same as other said here.
Well, first of all there is a good chance they do not know about them, secondly, as i've said, there are millions and millions of new ads added to adsense each day. These are getting checked automatically, which basically means they don't get checked until someone reports them. Then they'll get banned, but they'll just open up a new account and do they same shit.