Statements like, The company plans to pay them "regardless of their participation." make me think otherwise
I didn't read that as 'the company will pay them even if they explicitly don't want to be paid'. I read it as, 'the company will attempt to make contact and pay them even if they haven't yet signed up.'
I don't think it likely that many publishers will opt out, though. They'll still get ad impressions for the initial page load in addition to the kickback for the visitor's readability click.