Hi all. Just wanted to give a heads up after quickly reading the thread. Based on the first post, this would NOT be allowed by MaxBounty, and I'd be surprised if any network allowed it. Pretty much all networks have T&Cs which don't allow adult related traffic. So if you insist on trying it, please don't with our network as you'll almost surely get caught and booted.
Now let's say you tried this idea WITHOUT any attachment to adult content... well it would be allowed as long as you stick with campaigns which accept incentive traffic, don't mislead the surfer or give negative instructions in any way ("after you sign up, just unsub right away!"), use approved creatives and adhere to all terms.... problem then becomes what content could you password protect which you actually have permission to use.
That said, I suspect the quality of this traffic would be VERY low in either case and while you might not get booted from a network if you tried the non-porn version of this idea, you might find hefty reversals once the merchant checked lead quality, and almost certainly would be removed from advertising those specific campaigns in the future. You might even still get booted from some networks as you are arguably initially misleading the surfer by requring a password for content you most likely don't own.
A better, safer and longer term source of traffic (while not as revenue potent) would be to try a similar idea, but direct the surfer simply to YOUR site instead of a redirect to a sponsor. Gets eyeballs on your website, whatever that is, and some traffic will naturally flow through to your sponsors through approved creatives. I wouldn't try Havok's idea as a means of sending traffic to sponsors, but instead as a means of getting traffic to your website.