If you say it is so easy to read and de-select the buttons to "Opt Out" then it should be just as easy to select to Opt-IN. And if there are potential browser issues or ad-blockers that prevent people from seeing the options then you should err on the side of caution and again use the Opt-IN approach. It's a win-win for you and consumers. The fact that you aren't doing this (and Adobe has very smart people and lawyers so they have thought of this) means Adobe would rather use back handed trickery than doing the honest thing.