That "guarantee" is of no use unless you can prove it (which you can't from the outside - so much data goes into ad targeting that it's impossible to definitely

That "guarantee" is of no use unless you can prove it (which you can't from the outside - so much data goes into ad targeting that it's impossible to definitely prove which bit of data was used to target a given ad). They've also proven their bad faith with their GDPR consent flow that's not actually compliant with the regulation (there should be a big "decline" button as easy to use as the "accept" button).