Working with ad exchanges? Do these things:

• Require MRC accreditation
• Implement a whitelist-only policy
• Never pay for any impressions listed as “unknown”
• Require a full site transparency report every week

If the exchange will not agree to the above, drop it instantly and move on.

In addition, you should test your own ads with real humans every day. And have your marketing managers do it, not your interns. Not your ad agency. If you see one questionable website, audit the whole exchange immediately. If you see two questionable websites, pause the spend while the audit takes place.

A good article on what can go wrong is here at Digiday.