How?
> b) Who determines which ads are "unintrusive"?
Adblock
How?
> b) Who determines which ads are "unintrusive"?
Adblock
Regarding Adblock: b) I posted another comment elsewhere about how choosing which ads are "acceptable" or not presents challenges. There is a lack of objectivity. It should be a choice between ads or no ads.
[1] http://www.businessinsider.com/adblock-gets-sold-acceptable-...
Why do people post this nonsense. Their use is to block intrusive ads. They are very clear about it and every argument against this has been incredibly misleading.
Whether payment is required or not isn't even clear, because it is mentioned only as a potential.
The obvious conflict of interest from making payments even optional for advertisers makes them clearly untrustworthy.
Then I think your only option to remain logically consistent is to not install any ad blocker.