You don't need to involve ad providers. This is solely the decision of the site owner, who installs the topjoy widget. I don't remember where it was published, but there was evidence that regular visitors have near 0% CTR. Instead of relying on the $0 advertising revenue of your loyal readership, makes more sense to let them tip you and read your content. The added bonus of eliminating the advertising noise could increase tipping rate/amount. I'm not sure what else you have planned, but it may be good to focus on features that could increase tipping rate of loyal readerships.
Me for instance, I have ad blockers up, and I wouldn't mind tipping Economist or NYT $5/mo to avoid ads when I'm away from my home comp.
There was not enough incentive to pay for the gated content in NYT, and that gated content still had ads galore. Also, the monetization value of regular visitors that typically do not click on ads is near $0.
I think there may be some miscommunication.
Voluntary tipping improves the monetization of typically hard to monetize regular visitors. I'm suggesting that there are other things you can do to improve the tipping rate/amount from these regular visitors; one of them being to remove advertising from a site for a visitor when they tip past some threshold or something.
Me for instance, I have ad blockers up, and I wouldn't mind tipping Economist or NYT $5/mo to avoid ads when I'm away from my home comp.