Google DFP allows it because publishers (e.g. the New Yorker) aren&#x27;t ready to switch all their traffic HTTPS.  If they wanted to they could turn the switch and be HTTPS and tell DFP to only serve secure creatives.<p>One of the larger difficulties for publishers is that many of the 3rd party SSPs aren&#x27;t ready to go full HTTPs and so publishers are reluctant to make the switch because it reduces demand sources.<p>Disclaimer:  Work for Google in advertising