This has happened to me multiple times.
We're using GA tracking codes for each source (publisher). We're running a geo targeted campaign. We see insanely high (40%+ of total incoming traffic)Google Analtyics traffic from New York (not a targeted region).
We go to our Viewibility suite and find that the impression share is really low. A relative 4% of impressions served.
We keep finding that click bots are attacking from New York, increasing the clicks, boosting the CTR but they're all from outside our targeted region. The high CTR is influential and I believe this is a scam, regardless of whether we're paying by CPM, we should be able to select partners who are earning clicks not bots.
For national campaigns I'm not sure that we've been able to track it as well. So Click viewibility would be a great idea.