Possibly: it's not fully clear yet whether the GDPR requires you to offer people the opportunity to use your site without ad fraud detection, but I'm expecting it turns out it does. And without ad fraud detection ad-supported sites are mostly not practical.
You can have ad models that are immune to fraud. A time-based model such as "your ad here for X days" is immune to fraud, just like ads in print or TV are immune to it. If the ad drives purchases, the advertiser renews; if it doesn't, you may have to lower your price until another one comes up.
It's not immune to fraud: if I offer you ad space on jefftk.com how do you know how much to pay for it? Without some kind of fraud detection, how do you know whether to trust me when I tell you I have 25k unique visitors monthly?
