Nefarious publishers that defraud advertisers by using code to artificially play video ads are responding to recent attempts to shut them down using fraud-busting software, according to one ad tech vendor.

“People who create bots realize that now advertisers are focused on finding ads that are in-view,” says Integral Ad Science CEO Scott Knoll.

“So the bots purposely scroll an ad in to view … or sit through the whole pre-roll video or hit ‘play’ and watch the video. They’re smart enough to try and back in to the metrics advertisers are using. In a lot of cases, money to buy that ad is wasted.”

Integral uses a metric called True Advertising Quality Score, or TRAQ, to measure effectiveness of ad impressions beyond “viewability”, Knoll ads.