I think that most if not all of our users understand how it works, and many choose to use another email address.

It takes a few seconds to create a gmail address, which would not affect offer conversion whatsoever.

Also, we certainly avoid offers that subscribe a user to thousands of other lists...that's absurd.

I'm sure I've done CPA for longer than you my friend, and I certainly don't share the same level of pessimism.  Neither do our thousands of happy users