The verification server won’t know what e-mail address or credit card statement you used in order to get the badge, only that it was created by a particular issuer.
That's pretty clever but in case of serious leaks, and they do suggest it could be used by government employees, it doesn't provide much additional protection. Investigators will need two subpoenas/warrants instead of one.
Some verification services could simply not keep logs of what they verified, and documents they used. The problem here is that there is no way for the issuer to prove they really don't.
Heard is starting out by running one that verifies whether you’re a “tech industry insider” by checking to see if you have an email address from one of about 20 major technology companies.
Another problem is that your employer will know that you signed up for an anonymous gossip/leak site.