Here's a thought: instead of dealing with crap like this, what about a service for mailing lists that collects email addresses, and stores them internally.
Companies wanting to reach customers can put the signup form as js on their websites, but never get the actual email addresses. The mailing list service passes the newsletters on to subscribers, who are free to click links and form a more direct relationship with the client company, but guarantees to users that:<p>1. It will never directly pass email addresses to the client company or any third party.<p>2. All unsubscribes will be respected immediately.<p>So you can sign up with confidence. The downside for the client company is it doesn't get those sweet, juicy email addresses. The upside - lots more signups, and no fake addresses.