I spent a minute trying but no, I cannot think of anything that would make me go 'well fuck you' and go elsewhere faster then being expected to type out ad copy like a school child.
Interesting idea, but I would never watch an ad clip to signup for something nor would I want my users to have to.
This is actually attempting to solve two problems at once, and in some ways it could be more interesting to the user if the ads are well targetted.
Why not help the site owner make a bit of $$??? are you really afraid that typing in a bit of ad copy is going to turn you into a mindless drone
It's evil, but evil in a kind of clinically beautiful way. I'd say it stands a good chance of working in the short term too - like punch they monkey ads made a lot of money for some people back in the day
The only way to do that is if it works.
So yeah, I am concerned.