Only AFTER one has determined the webmasters aren't using abusive ad networks or practices, or both, to get those adverts to you. What you're trying to ask is:

Only AFTER one has determined the webmasters aren't using abusive ad networks or practices, or both, to get those adverts to you. What you're trying to ask is: do you white list once a website has shown itself to be decent? Yes, when and where I remember. Sometimes it slips my mind.