The ad serving companies (Google) don’t care about what happens after the click (yet). As far as I’m aware no “handshake” process exists that would allow an advertiser to communicate with the as server and validate a click (such a process could be abused).

Most likely the advertiser would be using some form of client side analytics, so the click wouldn’t show up in their statistics, meaning the advertiser would see a huge discrepancy between the clicks they saw in the campaign and the clicks the ad server reports.