Agreed. The whole point of mining is that it's a less obtrusive and less intrusive alternative to running ads. If you're going to show people a scary "opt-in" button from a separate page (which may be blocked anyway), it's easier to just ditch the idea and run ads instead.

What if they say no? Do you just block them from reading your site? Users will disappear as no one wants yet another account they have to click through just to check a site out.