If this is the case, then why do advertisers ask SEs for refunds, and why do the SEs give them (in some cases)? Instead of asking for refunds, they could just reduce their ad spends. Futhermore, the SEs could very well say that from the perspective of the service they render to the advertiser (the HTTP request for a sponsored link returns a redirect to the advertiser's site), it is working in good faith. They cannot guarantee the identity, or intent, of any particular requestor - all they can do is assure that the redirection occurs correctly and in a timely manner. But they have decided that they should issue refunds, and work with companies such as CF to combat fraud. This would suggest that the problem is more serious than can be resolved by merely reducing ad spend.