Bad guys have been auto loading ads and pages in the background, in hidden iframes, in 1x1 pixel iframes, etc. to get more quantity of impressions, while staying hidden and defeating fraud detection.

1. July 2018 / Page 1marketing.scienceconsulting group, inc.
linkedin.com/in/augustinefou
Auto-redirects – hidden iframe
Pages auto-redirect without human interaction, load more ads
Source: GeoEdge, Jan 2018
“Hidden Auto-Redirects,
… opens invisible
iframes, and
unbeknownst to the
user, goes on its own
delivery path, serving
and clicking on ads
automatically.”